Mustang Survival Sentinel Series Thermal Base Layer - Middle Weight TopFEATURES Designed as part of a full thermal management system, these two new base layer options have been constructed for optimal compatibility with Mustang Survival dry suits. Available in both a midweight and lightweight version, each solution will be offered as a two piece set made of the highest quality Polartec materials to provide utmost flexibility based on mission profile. Top and bottom sold separately. Made from a combination of Polartec