By toggling the switch, you reduce the power that is going to the heated undergarments and extend your burn time. Power levels available are 100%, 80%, 60%, and 30%. To reset back to 100%, simply switch the canister off for 10 seconds. The controller can be purchased as a stand-alone unit or integrated into the lid of a battery pack. A lid with an integrated heater controller will have a piece of red shrink wrap on the cord. It is recommended using heat control-integrated battery packs for heated undergarments ONLY. Plugging a light head into an E/O inline with a heat control board will cause damage to your light head and potentially void the warranty. Includes battery, canister, Heat Control v2.0 integrated lid, E/O cord, and charger Standard cord length is 12" (30.48 cm). 10 AMP Pack: Powered by two 5.2aH (57.5wH) Li-Ion batteries Length - 9" (22.7 cm) Diameter - 2.75" (6.99 cm) Dry Weight - 3.25 lbs (1.4 kg) Negative in Water - .75 lbs (.3 kg) Recharge time from complete discharge - 6 hours 15 AMP Pack: Powered by one 10.4aH (115wH) and one 5.2aH (57.5wH) Li-Ion batteries Length - 11" (28 cm) Diameter - 2.75" (7 cm) Dry Weight - 3.9 lbs (1.7 kg) Negative in Water - 1.3 lbs (.6 kg) Recharge time from complete discharge - 9 hours UN 38.3 Test Compliant - BATTERY IS SAFE FOR AIR TRANSPORT 20 AMP Pack: Powered by two 10.4aH (115wH) Li-Ion batteries Length - 12" (30.48 cm) Diameter - 3" (7.62 cm) Dry Weight - 4.95 lbs (2.2 kg) Negative in Water - 1.6 lbs (.7 kg) Recharge time from complete discharge - 12 hours UN 38.3 Test Compliant - BATTERY IS SAFE FOR AIR TRANSPORT 30 AMP Pack: Powered by three 10.4aH (115wH) Li-Ion batteries Length - 12" (30.48 cm) Diameter - 3.5" (8.89 cm) Dry Weight - 7.5 lbs (3.4 kg) Negative in Water - 1.7 lbs (.7 kg) Recharge time from complete discharge - 18 hours UN 38.3 Test Compliant - BATTERY IS SAFE FOR AIR TRANSPORT