I ultimately bought four of these -- three in blue and 1 violet. Following eye surgery I had over four weeks of constant eye pain. Using a frozen cooling mask was the first relief I had. I bought multiples so I would always have one ready.
I freeze them for longer than recommended (for convenience) and apply the cloth side to my eyes. After the mask defrosts I flip it over to the plastic side for another 20 or 30 minutes. Frequently I fall asleep with it on.
There were slight differences between the blue and violet masks-- the blue ones have what looks like little gel beads (like tapioca) in liquid gel. The zip bag they came in were a tight fit. The violet mask was filled with all liquid gel and it came in a better fitting bag. They all work great. I substituted zip lock bags for the blue ones. I do not like to put them in the freezer next to food without bagging them.
The masks were a great buy and I still use them after my eye situation fully resolves as they are helping me fall asleep. A side benefit has been no more puffy eyes. These masks have been a life saver for me

Everything was fine. Made well froze up like it was supposed to. I just couldn't handle the extreme cold. Going to try just keeping in the refrigerator.

large, with one side covered with fabric for a more subdued cold

This is a review for 3 different silk sleep mask products I ordered all at the same time, which I picked out based on information from both sleep mask review sites and amazon reviews.

Alaska Bear Silk sleep mask
Jimoo Silk sleep mask
BeeVines mulberry silk sleep mask (2 pack)

The design of these masks are all very, very similar. Their size, shape and strap adjustment are all nearly the same with only minor differences. As one might expect, because of this I found all of them performed basically the same.

Common complaints I noticed when looking at sleep mask reviews were:

- Dye from mask bleeding on pillow/face.
- Strap adjustment plastic being uncomfortable as one's head laid on it.
- Mask putting pressure on the eyes from being too tight.
- Light bleeding in/ under mask around nose, or through the mask itself.

Addressing the common complaints of this style of sleep mask mentioned above:

- I have had no issues with any of the 3 products bleeding dye. I wash them in room temperature water with soap nut liquid, rinse, press (not wring!) the excess water out and hang to air dry.
- The plastic strap adjuster can be a bit uncomfortable at certain angles, depending on where it is and how you tend to lay your head when sleeping. See more details under the specific product reviews.
- At first I also thought this was an issue, because I hadn't loosened the adjustment strap enough. You really want to loosen it more than you think you do, it'll stay! For me I found once it no longer put any pressure across the eyes it was about right. There is a slight trade off of the mask shifting a little if you toss your head around a lot during the night but it's easy to shift back in place even if you're mostly asleep.
- There is a slight bit of light bleed around the nose, most noticeable if the mask has shifted to one side or the other during sleep. It's generally not been an issue unless your sleeping under the sun/ very bright light, or the light happens to be angled low such that it's coming from your feet up towards your face. There's been no issues with light coming through any of the masks.

As for specific things to note about each one:

Alaska Bear
Natural Silk Sleep Mask, Blindfold, Super Smooth Eye Mask (White)
https://www.amazon.com/gp/product/B07L8RYFWF/ref=ppx_yo_dt_b_asin_title_o06_s01?ie=UTF8&th=1

Of the 3 this was the only one with a small ID tag sewn into the side near where the strap attaches. It hasn't gotten in the way or been noticeable. There's several cute patterns/ embroidery options, but it was the most expensive of the 3. The adjustment strap size is the same for Alaska Bear and Jimoo. For my average-sized head the plastic adjustment mechanism ends up off center-middle-ish of the back of my head, making it slightly less comfortable for back-sleeping.
J Jimoo store
Natural Silk Sleep Mask, Super-Smooth & Soft Eye Mask with Adjustable Strap (Grey)
https://www.amazon.com/gp/product/B07X1454P8/ref=ppx_yo_dt_b_asin_title_o06_s01?ie=UTF8&th=1
I appreciated that this one came in several moderate mostly unpatterned shades other than black/ white and had no embroidery. As there's no embroidery you can reverse it and use the other side as well between washes. Of the 3 it feels the thinnest yet still has no issues blocking light. As it's thinner it drapes slightly better than the other two. The adjustment strap size is the same for Alaska Bear and Jimoo. For my average-sized head the plastic adjustment mechanism ends up off center-middle-ish of the back of my head, making it slightly less comfortable for back-sleeping.
BeeVines
Silk Sleep Mask, 2 Pack Mulberry Silk Eye Mask with Adjustable Strap
https://www.amazon.com/gp/product/B08LTGMVBX/ref=ppx_yo_dt_b_asin_title_o06_s01?ie=UTF8&th=1

This one was probably the cheapest per mask, yet hasn't lost out to either of the other two except in one place: color/ decoration options. It does have a smaller adjustment strap than the other two but as long as you don't have a super large head there should be no issues. I think I have a fairly average-sized american head and this fits just fine, though I have it nearly all the way loosened. As such the plastic adjustment mechanism is at the side of my head on this one and not as comfortable for side-sleeping.

This thing is a solid value for the money. Gets nice and cold, also pretty comfortable. If you're looking for this sort of thing would def recommend