Automotive Firewall Plug. Plastic Enclosures: Cover knockout holes in project boxes or junction boxes. Hole Plugs. Tubing Plugs. Fits 1 3/8" Hole | 1 5/8" OD | 1/8" Panel Thickness. Firewall Rubber Hole Plugs 7/8" to 2 1/2" Push In Compression Stem 10 Sizes.
eBay