COLPAC COLD PACK provides an instant pain relief to treat fever, bruises, sprains, strains and helps to manage swelling. Patented design of the ColPac gently delivers soothing cold therapy and stays pliable during treatment. Each pack is filled with non-toxic silica gel that remains pliable during treatment that can be used for up to 30 minutes at a time to reduce acute pain, swelling, and fever. To recharge the Blue Vinyl Colpac, place it in a chilling unit or a freezer.