OIL PLUG 30MM - VENTED! Another Brand M Exclusive! Made In USA! Properly vented to relieve pressure buildup but prevent rain from getting in Fitment Note: Some models have a 30mm plug and some models have a 20mm plug. This is the 30mm version, which is just a little over 1-1⁄8 inch outside thread diameter. The 20mm version is approximately 3/4" outside thread diameter. Includes: High Quality UV Resistant Plastic Cap Oring Replaces: 1A1040-48060 194200-24380 794200-24350 794210-13750