Murray Roller Pulley part# 672781MA is 7/16" tall, has an outside diameter of 3/4", and an inside diameter of 1/2". This backside idler is used in the drive system of the following self propelled walk behind mowers; 21595X31B, 21595X8A, 21595X8B, and 21595X8C. There may be models that use this part that we do not have listed here. Please refer to your owners manual or a parts breakdown for your model, to assure that this is the correct part for your machine, before you order.