Use to remove and replace oil pressure sending units on 1987 through current GM engines with dash gauges including 2.0, 2.3, 2.5, 2.8 and 3.0 L used in Chevy, Buick, Olds, Pontiac and Cadillac cars. Hex opening is 1-3/16_. Turn with 1/2_ square drive tools or 15/16_ wrench. Length: 3-1/4_.