My girlfriend uses these for her severe plantar fasciitis. After teaching for a year and not stretching enough, she got to the point that she can hardly walk and is in extreme pain in her right foot constantly. She has tried rollers, compression socks, ice packs, muscle relaxant topicals, and much more, but these splints are the first product that could actually make a noticeable difference. She can now walk normally (rather than limping on her right foot) after about 5 nights. The problem with plantar fasciitis is that you heal the damage done during the day while you're sleeping, and if you (like her) sleep with your toes pointed, your muscles along the back of your foot heal in a shortened state. The splint forces you to keep your toes up, so your muscles can start to heal in a longer state and not rip up again as soon as you take your first step. If you have similar severe plantar fasciitis, GET THESE!!! If you are like her and your podiatrist sold you inserts that don't fit in your shoes, consider that those custom inserts are much more expensive for you and thus more profitable for them than these cheap but effective splints. Don't listen to them, get these splints or some like them.

Now for the cons: they are pretty bulky. If you are a light sleeper you WILL lose sleep to them. We ended up purchasing a second splint as armor against the first after a few nights because her left foot was getting roughed up by the hard plastic. It is also very difficult to keep your feet under the sheets with these on, so expect to wear socks. Lastly, you can expect the healing process to transfer the pain and tightness from your plantar fasciitis to your calves and ankles, so be prepared to stretch them constantly.

I purchased this item twice. Once about 3 months ago and it worked so well for my plantar fasciitis that I bought another for my other foot because I could feel that one hinting towards symptoms of plantar fasciitis. Although I still live with the plantar fasciitis, this boot provides support and prevents pain while I sleep and also that first step in the morning. (My plantar fasciitis came about when I was training for a half-marathon and I must had the wrong form.)
Now, the first boot was perfect. HOWEVER, the second boot I ordered came in around 2 weeks ago. It looks the same but the straps are different. In fact, I had trouble tightening it. So upon closer examination I find that this second boot is defective. The Velcro straps are too long and don't have Velcro all through the strip. There are buckles on both sides of the boot instead of just one side, which makes it harder to tighten. Even when I attempt to tighten it by folding the velcro strip over itself, it still comes loose and doesn't provide any support.
I gave 2 stars because the first one great, but the second was terrible. I will be requesting a replacement and hopefully they send me a good one.
Update: the replacement was the same as the first one so I just had to make it work even though the velcro was too long. Overall, I have increased my rating because THIS PRODUCT WORKS! I have been two of them since I posted the first review and now it feels like my plantar fascia are healed. I have corrected my running form and I must let you know that I am only running a max of 4 miles at a time. Most of the time I am running 2-3 Miles and if I go over 4 my feet start to ache again. I also use KT tape on my long runs, I wear only shoes with good arch support and I do the prescribed stretches for the plantar fascia after the run or whenever they start to ache.
I am still using both of my splints so they are well worth the money.

UPDATE2:
I was able to fine tune the adjustment and now I have a snug comfortable fit. Although I've had two theraputic massages to loosen my left leg/ankle/foot, I know the boot was helping. Each day I feel better and better. My left is so much better, I'm starting to feel the right foot pain more, so I'll probably start swapping the boot back and forth. The boot also, surprisingly, doesn't bother me in my sleep. I consider this a good buy.

UPDATE:
First, the shipping on these was unbelievably fast for not being Prime. I received the small, and even with the little amount of strap adjustment left, it's still a little loose around the calf and I have pretty good sized calves. In addition, because it's a small, my toes hang over just a tad. Besides that, I really like the boot. Because it is smaller, it's less intrusive. I'm going to create a little extra padding around the calf area, and maybe a wedge for the ball of my foot/toe area. I'd recommend it, but go much smaller than the chart suggests.

ORIGINAL:
I wear a 10 mens. I ordered a medium (7.5-9.5) because of all the reviews that talked about sizing issues. It was way too big! IThe straps were already as short as they would go and it was no where close to even snug. That being said, I will say that whoever complained about difficulty putting it on due to placement of buckles may have been using an older model, because mine has buckles on both sides of all straps. I was able to unbuckle the straps with my eyes closed. I find the shell rigid yet light, and the overall size didn't bother my sleep. So, I'm going to return the Medium and try the Small, because besides the fit, I think it's a good product. The company should really update their sizing sheet. It's not like it hasn't been commented on MANY times.

In an effort to help others with plantar fasciitis, let me tell you what worked for me after 8 months of PF, 2 dr visits and 4 weeks of PT -- it wasn't the dr and PT, although my physical therapist did help. PT had me do ankle pumps (30 when I wake up each morning) and eccentric calf raises every other night 3 x 12 with an aerobic stepper (KLB Sport 27" Adjustable Exercise Equipment Step Platform). Every other night 3 x 12 x 2 of the first two exercises with this ProStretch Calf Stretcher and Foot Rocker (The Original). I continue to do all of these every other night. While continuing that I have used a let's try everything approach to end this ASAP. While the exercises have helped what really put me from 70% better to 95% was the following:

Plantar Fasciitis Posterior Night Splint (MARS Wellness) -- much better than an earlier one I had tried from Futuro. This looks big and bulky but actually is more comfortable at night. The futuro also made parts of my foot go numb.

Beurer Foot Massager With Built in Heat Function, Shiatsu like Features -- use this 45 mins a day at night with heat. I use it lightly at first until the foot warms up (5-10 mins) then apply pressure to the heel area. PT explained there are ligaments and fibers that need to be disrupted/torn up a bit in the heel. This works wonders for that. It is a bit painful at first but the heel gets numb as you gently increase the pressure down on the heel.. I hope to not need to do this forever, so far about 1 week, and it seems to be helping a lot.

Sof Sole Arch Full Length Comfort High Arch Shoe Insole for Men and Women -- I also tried and like SuperFeet orange and yellow. These to me are better as the heel is cushioned. I use these now in all my shoes and footwear. They help but the are not a cure. Hopefully once I am back to 100% these will help stave off future flare ups.

Fish oil supplement -- 1 per day. This is an anti-inflammatory without the long term problems of using an NSAID daily.

Penetrex Pain Relief Therapy -- not sure it does anything but am continuing to try this. If nothing else it feels good to apply 2 or 3 times a day.

TheraBand Foot Roller -- PT recommended this but I did not find it helpful. It does not allow enough pressure on the heel to disrupt whatever is going on there that needs to change. I replaced use of this with the Beurer Foot Massager which for me works much better.

I hope this helps someone else with these issues. I am hoping this regimen will fully cure the problem in another 2-3 weeks.

This Plantar Fascitiis night splint has been a real game changer for me.
After seeing my foot doctor for God awful foot pain when getting out of bed, and listening to his explanation of what causes Plantar Fascitiis .... wearing these Night Splints made perfect sense.
I suffered for about a year ....thinking my foot pain was the beginning of arthritis. Morning after morning getting up and experiencing this debilitating pain but having it would ease up as I started to walk around was baffling. I would forget about the pain during the day, only to awake up to the same problem the next morning. It wasn't until I developed a heel spur that I knew I needed to see a foot doctor. He explained that at night when we go to sleep our feet tend to arc up a little in its relaxed state. The body will start to heal any ligaments overnight and and after putting your feet down on the floor and stretching them out flat the next morning, the healed ligaments get tiny little tears again where the ligament attaches to the heel bone causing this terrible pain when trying to walk the next morning. So night after night
when the body is at rest, the body will lay down calcium because of repeat tearing, causing a painful heel spur to develop. But that's where this amazing Night Splint comes in, and what it's been able to accomplish for me in a short amount of time ! The theory behind this is simple:
Keeping your feet in a stretched out position while sleeping (like during the day), the ligaments can heal while in correct position. So when raising from bed and removing the splints your feet are already in the stretched out position, therefore you won't be tearing your healed ligaments ! Please note I now also put on good supported sneakers before standing up from bed per doctors instructions.
So thrilled to report that after wearing these splints after one night of sleep (possibly 5-6 hrs.) I can honestly say getting up the next morning was traumatic, it felt like a miracle .... I had relief from my Plantar Fascitiis ( worth repeating, if plantar Fascitiis is left without being treated you can develop a heel spur, excruciatingly painful condition).
Per my doctor, I only now need to wear my splints at night if I've had a long
day on my feet and feeling any discomfort, but if no discomfort during the day, than you don't need to wear at night, because the body doesn't have to heal damage from the day..... Very important to listen to your foot....if their crying your doing damage! Please learn from my hard lesson.
Healing my heel spur is another story .... I've received first shot of cortisone and had the need to be a couch potato as much as possible for two weeks to help speed healing. Now after two weeks, and a second shot of cortisone due to lingering inflammation, I will be going for physical therapy 2-3 times a week for 8 weeks. In the meantime I will continue my Night Splints as needed, because they continue to play an important roll in the healing of my painful heel spur. Oh and one last thing, I am wearing good supported sneakers ,and shoes with orthotics - it's extremely important to have good foot support. I say this after wearing my beloved flip flops for years and my ballet flats..... But fear not, they make brands out there with great support.
I wish anyone suffering, a speedy recovery ! .... and wearing this Night Splint per instructions from your doctor.... will help you get to the light at the end of the tunnel !