DANCO 1/2 in. Rubber Washers (2-Pack) 10401 - The Home Depot
Rubber Sheets & Rolls at Lowes.com
Flat Rubber Mat Platform 8" x 9" - Southwest Science
Black Rubber Washer Large Rubber Washers 1 1/4" OD x 3/4" ID x 1/8" Thickness - EPDM Rubber Washers Flat Rubber Washers Round Rubber Washers (Pack of 12): Amazon.com: Industrial & Scientific