Kastar 8586 Ratcheting Serpentine Belt Wrench

15mm, 16mm and 3/8" Square. Designed to release the tension on spring-loaded idler pulleys. Will service approximately 90% of all vehicles equipped with a spring-loaded tensioner pulley. Allows direct access to the tensioner. Heat treated and nickel chrome plated for durability, appearance and long tool life. Made in USA.