Bullard revolutionary Isotherm technology offers unparalleled cooling power. Unlike ice or gel packs that stea-dily lose their effectiveness, Bullard Isotherm Cool Vests will remain at a constant 55° F for hours of cooling. Isotherm can help reduce the chance of heat-related illnesses that sometimes occur in today’s difficult work en-vironments. Isotherm is lightweight, quickly recharged and does not leave condensation. It uses a simple, inter-changeable, front/back cool pack system that provides continuous cooling to the worker’s upper body. The vests are easily adjustable for maximum comfort and flexibility.