Polar Tech RE-FREEZ-R-BRIX RB30 Foam Refrigerant Packs, 31oz Capacity (Case of 6)RE-FREEZ-R-BRIX is a block of rigid foam that holds its shape frozen or thawed and is reusable. These refrigerants are non-toxic, sealed in a heavy plastic pouch, and are rated the best in foam refrigerants. Other products just don? compare.Features of Polar Tech RE-FR..