The Grip Heater Custom's assembly is constructed from several parts from which the Grip Heater Kit is the most expensive.
Some items from this specific schematic: Heater L Grip, Bracket Sw, Grip Heater Sw, Grip Heater Kit.
The most reasonably priced component used on the Gl1500c Valkyrie 1999 (x) Austria Grip Heater Custom's is the Bracket Sw.