ITEM NAME:Double-end Car HVAC Valve Core Remover Changer Installation Removal Tool #gib Store Home Promotion Hot Item Add to Fav.Function: the small end is used to twist the Schradar valve core, and the big end to screw the big valve core. 1 X Double-end HVAC Valve Core Removal Tool. Add to Fav. Products suitable for: trucks, engineering vehicles, forklifts and other large vehicles.