There are 2 different types

Standard
2 layer structure, non-woven underlayer enhances rapid absorption of water when activated,  plastic toplayer allows for an easy and fast freezing process. It is reusable, multiple times and the cheapest alternative available.

De Luxe
4 layer structure, microperforation in the lower  plastic layer allows for wtaer absorption and transforms your Ice pack XL into flexible cushions. The non-woven layers  in between allow for extra suport and guarantee an extra long lifespan. Therefore your Ice pack XL  can be reused over a much longer time.