☆ Effectively cools the body from the back. ☆ Backpack type, so your hands are free and convenient! ☆ Cooling sensation lasts with the ice gel pack! ☆ Insulating aluminum sheet included to prevent cold air from escaping! ☆ Adjustable size on the elastic straps. Moderate thickness for a comfortable fit! I bought this for my son, but he said he won't use it, so I'm selling it. - Thank you for looking.