7 Volt / 3.5 foot Extension Cable: The 7V Extension is an optional accessory for use with the 7V heated clothing. Once connected, the 3.5' cord provides more options for 7V battery placement. This is a useful accessory to pair with the balaclava, any mid-layer, or when you just need a little extra cord length. 3.5' length. The extension is compatible with other heated clothing brands that use the common 3.5 x 1.35 mm plug. 12 Volt / 18 inch Extension Cable: The Extension Cable provides additional length for your coax connections. 18" length. Maximum capacity: 15 amps.