For adjusting idle/mixture screws on many GM and Chrysler vehicles with carburetors. Includes: Carburetor adjusting tool, "Double D" adapter for Gm '79 thru present, 1/4" hex adapter for pre '78 GM, 3/32" hex adapter for '78 thru present Chrysler 1.7-2.2L engines, 4.5mm hex adapter for '78 and '79 GM