The Portabrace POL-PMW300 Polar Mitten Camera Case is designed to keep your Sony camera functioning properly in cold weather. The case is thickly padded with high-loft insulation material. Air-activated warmers are placed along the case interior to keep battery, recorder, lens and hands warm in extreme cold temperatures (tested to -50°F). The insulated lens cap protects the lens in transport and also prevents condensation from forming when bringing the camera in from the cold. Each Polar Mitten Case comes with 4 air-activated heat packs.