Harkila Heat Jacket is an exciting innovative addition to the Harkila shooting clothing range for a higher degree of performance keeping you in control of your comfort. Harkila heat technology uses a thin membrane to warm your body which is safely powered by a power pack in your pocket (not included) and controlled by a button or a control app on your smart phone. There are two heat pads - one between the shoulder blades and the other on the lower back. This smart heat jacket has comfortable stretch side panels for a streamline, comfortable fit with Thermo Polyshield padding for extremely warm lightweight, packable insulation. Available in Willow Green/Black in sizes XS - 4XL Main fabric is 100% Polyester, 20 Denier - Polyknit with WR Polyurethane coating for a durable long lasting performance Lining: 100% Polyester, 20 Denier Poly knit. Heat reflecting silver print to keep the heat in Padding: 100% Polyester - Thermo PolyShield Insulation created from super soft fine Polyester fibres for a comfortable loft and touch that's lightweight and quick drying Double heat panels for maximum warmth and comfort in cold weather Zipped chest pocket on the left hand side Stretch fleece panels for comfort and freedom of movement Reflective heat lining to keep the warmth around your body Side-zip pocket and stow pocket for power bank Power pack not included, but can be powered by any USB power pack available at many electrical retailers Elasticated collar sleeve hem and bottom hem to hold in the warmth and keep the cold Soft microfleece inside the collar for soft warmth Button with three temperatures for manual setting Size: XS - Chest 90-94cm, S - Chest 94-98cm (37-39"), M - Chest 98-102cm (39-40"), L - Chest 106cm (42"), XL - Chest 110-114cm (43-45"), 2XL - Chest 114-118cm (45-46"), 3XL - Chest 122-126cm (48-50"), 4XL - Chest 126-130cm (50-51")