Heated collars from L. T. & E. keep valves from freezing. Made of 304 stainless steel, collars are available in 3-, 4- and 6-inch sizes. Connected to the cooling system, the collars circulate antifreeze and are bolted between two flanges (ANSI or TTMA bolt pattern). They include extra pipe couplings for installing the optional 110-volt heater and thermostat for freeze control when the truck is parked overnight. 800/296-8035; www.ltetanks.net.