These are shipped vacuum sealed so they have to be reconstituted to their original size. The instructions give two methods, one simple, and one more involved. Not being in a hurry I took the simple route of leaving them to sit out for "24-48 hours," but after 48 hours some were virtually unchanged, and only three were mostly ready, as the image shows. The water and clothes dryer method is the only workable path, but be aware that the time indicated to be in the dryer was not sufficient to completely dry them out. They initially felt dry on the surface, but it turned out they still had considerable internal moisture.

These acoustical panels function as advertised, are consistent in shape and cut easily. I found that double sided adhesive tape did NOT work well and released fairly soon. I used Gorilla tape, not an off-market brand. I found that rubber cement worked extremely well and have had no releases in the last 6 months. The main drawback to these panels is to get them to re-inflate in a timely manner. When following the "preferred method" it took days for them to dry, no matter repeated trips to the dryer, and this is in the Arizona desert! I found that spritzing both sides with a sprayer then put in dryer worked best. Do not dry leaving in the air to expand, unless you are much younger than I am :)

Let me suggest you do not wait 24-48 hours for self expansion as it will not happen. This is said over and over - it is not a lie.
If you need a large volume like I did you may want to consider panels that are not vacuum sealed.
I bought 300 of these panels for my dog boarding kennel so I needed a quick way to get these to expand. I opened the first box that had 7-12 packs, peeled them apart while throwing them in my bathtub full of water (which worked!) but soon realized, too late - I was on a mission -I had to wring each one out with carpal tunnel syndrome and still had to dry them because no amount of squeezing was going to work. My dryer being fairly new has a moisture sensor I cannot figure out how to shut off. Due to that the dryer turned off every 3 min because the foam holds the moisture deep inside. These are SPONGES!
So here are my practical tips after trying several science experiments:
Rinse and Spin one pack at a time in your front loader. This alone will save you hours.
I'm using the steam cycle on my dryer because the water is disconnected. They get almost completely dry and doesn't shut off as often.
I'm sticking them to the walls with acoustic panel glue in a bucket. Then, using fans in the boarding kennel to completely dry them out and I'm sticking them to FRP not drywall so the initial moisture doesn't matter.
No doubt they help with the acoustic dampening.
I do not hate them but they are a pain in the hinder.

PRO: Yes, they do shrink and vacuum seal this foam to save space on shipping. Yes, they look terrible when you unwrap. But FOLLOW DIRECTIONS on the package and all is well. Get them wet, then wring them out. This is not a minor spritz with a mister bottle, this means saturate them with water. Both sides. Wring them out. Clothes dryer for 20 minutes. Perfect shape. They expand and look great. I agree 100% with another reviewer who said they work fine if you know how to follow directions!

Don't know if this makes a difference or not...we don't use dryer sheets but have those tennis ball things in the dryer. Don't know if that makes a diff, I doubt it, but the foam fluffed up fine.

CON: They ARE NOT 12" x 12" !!! They are really 11 1/2 x 11 3/4. I should have measured first. I cut some 1/4" plywood to glue them to, and they DON'T FIT because they are NOT the measurement advertised! There are gaps...would not have been gaps if 12x12 but they are short. Really? one foot by one foot works in my plans, but they don't measure up! This really sucks.

The instructions say to soak the panels in water, wring them out and then put in the dryer for 20 minutes. I followed the instructions and it worked fine. For soaking them I just dipped each panel in a bucket of water for a few seconds and then wrung them out. I did this very quickly. Just a few seconds for each panel. Then I put them in the dryer for 20 minutes. When I took them out of the dryer they had expanded and were ready to go.

I have used a different brand in the past and they expanded automatically after I opened the airsealed bag. I was surprised that I needed to soak these and do the whole dryer routine. But it worked out fine. No big deal.