Warm caulk flows freely, and fills better, resulting in smoother joints with better adhesion and sealing. Caulk Warmer warming bags will keep caulk at 80° even when the outside temperature drops to -13°. There are several different versions of the Warmer... Some are bags and others wrap around a bucket, propane cylinder, or canister of spray foam.
The best seller is the basic Caulk Warmer 12 Tube bag. The heavy duty nylon canvas bag has a back strap with a “quick disconnect” for looping over railings, plugs into 120V AC or 12V DC inverter, requires only 50 watts of power, and has a convenient cord storage pouch on the front. There is a convenient on/off switch and the internal temperature is thermostatically controlled. The Caulk Warmer holds 12 (1 case) standard size caulk tubes, or 7 quart size tubes, or 12 sausage size tubes, or 7 cans of foam, or a case of floor tile.
Other suggested uses include temperature sensitive products such as insulating foam, windows & door sealing tape, grease cartridges, adhesives, welding rods, and more. In addition to these items, there is one other thing we recommend putting in the bag – spare gloves so when it's really cold, you can change into ones that are nice and warm!
https://www.bigrocksupply.com/store/p/7197-Junior-Caulk-Warmer-4-Tube.aspx