***Update 1***
After posting the review below, the company contacted me within a day to apologize and offered to send an entire replacement mask and snorkel. I was quite surprised at this. They also indicated that the outside shell is the same for all sizes, but there is a chin opening for the L/XL sizes, so they really are not the same. I will update once I get the replacement mask. I was very impressed with their Customer Service!

Original Review: On the 1st time using the snorkel mask in the ocean, the breathing tube snapped off (in 3-4' waves) and I wasn't able to find it. I know it was on securly, but I do NOT recommend this for ocean use, as I practically threw the $30 away on this mask.
For the 3-4 minutes I was using it, the fit seemed very snug. I expanded the straps to fit my head, and it did fit and keep my eyes dry. However, we purchased a S/M mask a few months back for my 7 year old daughter, and when I compared the 2 masks, they were EXACTLY the same size. I'm not sure if the fittings are different or not, but there is no difference in measurements. With that said, I was able to fit into the L/XL one I ordered.
I really wanted to like this, but when I came out of the water, a lady asked me if I lost my air tube. She was going to drive into town to get one, and wanted to know how I liked it. I could not recommend this brand to her, based solely on how quickly the thing came disconnected.

So I took a gamble on this one.. I purchased a used condition snorkel face mask from Amazon and figured it was worth a shot. I'm very pleased with it- both my girlfriend and I tested it in the pool yesterday and I was pleasantly impressed. It works great as a simple floating snorkel system (for those who don't want to go underwater and get water in their ears, but it also works very well in 8ft underwater. I did not see more than a simple drip across the lens when I was swimming around at the bottom of the pool, and I had a very clear field of vision. This is SO much better than wearing goggles with a separate breathing apparatus. I don't know why anyone would ever buy one of those again.
Since we're going to Jamaica next spring I'm going to purchase another one of these to bring with us.
The top portion (breathing pipe) of the snorkel easily detaches so you can safely pack it away from travel (in your suitcase), which is a huge plus, too. Cannot beat the price, and the quality appears to be great.

First I need to tell you I am Scuba Diver since 1978. In my Scuba times I did come across all kind of equipment. "Pro Grade" and also not so much pro grade. This masks is designed for only surface snorkeling. Do not attempt to go down deeper than 2-3 feet of water. You have no way to equalize pressure for your ear drums. Depend on your condition may be you don't need equalize the pressure for 5 or more feet. If you attempt go deeper you may permanently damage your ears.
Pros: Nicely manufactured product. Easy to assemble and easy to use for it's purpose.(Surface snorkeling only !!!) Attachment for GoPro works well, just adjust angle before first filming under water to get recorded what you see. It will take you some time, but once you get it in right position just make a mark for next time easy set up. Breathing is easy and take little time to learn how exhaust properly to not get fog on the lens.Otherwise it is (In clear water, we did try it in Florida Keys- Islamorada ) lots of fun.
Cons: Once again! Do not attempt deep snorkeling. Snorkeling device with small plastic ball some times lock after you exhale in closed position not allowing you inhale. Not a big problem for experienced snorkeler, but a kid or new person to snorkeling can panic from not to able to breathe for a second. I had to blow rest what in my lungs to release the ball an be able to inhale again first time. After that I kept portion of air in, so don't exhale completely. Just make shallow breathing. Also this happens only at certain angle of the head, mostly looking straight down, when snorkel submerge and close the air path of snorkel to not get water in the snorkel by plastic ball and person exhale all air. Second, there is no 180 degree view. Our eyes are not fish eyes and I never saw in my life 180 degrees at once. It give you nice view lot better that conventional mask, but not 180. Also pricing is high in my opinion that this equipment is worth.
This item was purchased for discounted price for unbiased review.

So I've been snorkelling since I was small. I was a bit skeptical that this would improve my experience since I was used to the snorkel anyway. I even liked blowing the water out after dive. That being said, I really like this facemask. I am not sure the pipe is as large as a snorkel so for those who need more air, this might be a problem. There is a ball that covers the hole so water doesn't go in. Most of the time, the water didn't go into the pipe, I think if you catch it at the right angle, some water may trickle in. That is a problem if it is salty seawater because the pipe is right above your forehead and subsequently trickles down to your eyes. If you swim properly and use it properly, I don't see this as a problem. Some people who are used to snorkelling may feel odd when they dive with it because the pipe will close and if you try to breath, the mask tightens around your face. Another thing I noticed is that if it is wavy, the thing is easier to fly off your face. The old snorkel has the tube in your mouth so you can't lose I unless you open your mouth.

Overall though, my wife and son loved theirs. They gag at putting a snorkel in their mouth. I also enjoyed using it and I would recommend it to anyone.

Just remember, don't put sunblock on your face as that makes the silicone slippery and let's the water in as well.

Snorkeling masks can have two major issues: Fogging and water seeping through the edges. I have used numerous mask and snorkel sets that do a great job against it, but mouth comfort can be an issue from prolonged snorkeling, also.

I initially saw a demonstration from a video about makes like this, and I wanted to see how well it works. Assembly involves placing the breathing apparatus onto the mask. The mask has a mount for a Go Pro which I didn't test but it is in a proper spot for it which doesn't interfere with the vision or breathing components.

The mask fit me perfectly. I could feel how secure the seal around my face was. Breathing does take a bit of a learning curve for comfort since I feel like the flow of air could be improved. It feels like I'm getting 90% of what I usually do with conventional snorkels.

This imparts a very clear view. The edges have corners which do change the appearance when you look to the side. I wish it were more rounded than angled. I did various tests, such as prolonged snorkeling, front flips and back flips. No issues except with a back flip in water which caused a rush of water to fill in the mask.

The breathing apparatus has a one way valve which prevents back flow of water into the mask. Some water does reflex into the mask but it can be blown out the vents.

Fit is perfect and I didn't have issues with leakage in normal snorkeling positions. I didn't feel excessive pressure on my face or the mask edges. It's a wonderful design for comfort.

Overall, I'm pleased, but I do feel like the air coming in feels a little more restricted than I'm accustomed to with conventional snorkeling apparatuses.