We supply our construction customer hundreds of thousands of these custom injection molded plastic spacers in a variety of sizes and colors.  Recycled material is used for both the grey and black version shown here and both have a width of 15MM but all over dimensions vary.  The larger grey spacer has an ID of 18.4MM and OD of 52.7MM while the black spacer has an ID of 11.125MM and OD of 48.72MM.  Both parts are supplied through multiple releases from 12 month blanket purchase agreements established with our customer.