Valve Lash Wrench Set 9/16 Inch Wrench Stainless Steel Natural ProformT Handles. This simple T handle and wrench set makes adjustment very easy, cutting the adjusting time in half. Simply position the adjusting handle wrench over the rocker arm lock down make sure you have purchased the set with the proper sized wrench and drop the appropriate T handle down through the hole in the wrench with one hand doing the job of two! Then make the lash adjustment with a feeler gauge according to the camshaft manufacturer