OTC Tools OTC 4645 Serpentine Belt Tool. Fits tensioner pulleys with 13mm-16mm, 18mm hex or 3/8″ and 1/2″ square drives. For hard to access tensioners; there are 13mm and 15mm 12-point wrenches built into the handle. 13mm, 14mm and 15mm crows foot wrenches also included.








