OTC's Rocker Arm Shaft Socket is a deep-well 12mm socket used to torque rocker arm nuts to OE specification Specially designed socket features a stepped outside diameter for proper clearance and access to the fastener Applications include Detroit Diesel Series 60 engines Specifications: 12mm, 12pt socket; 1/2 inch square drive; High-strength, heat treated steel construction Similar to J-44706; Made in the USA