Crafted-Brand Heavy Duty Spacers – 1/2” OD, 1/2” Length, 1/4” ID for Screw Clearance, Unthreaded White Nylon 6/6, Never Rusts and Lighter Than Aluminum or Steel (Pack of 10 Spacers): Amazon.com: Industrial & Scientific
Amazon.com: The Hillman Group 58199 Nylon Spacers, White : Industrial & Scientific
0.375 in. ID 0.500 in. OD 0.688 in. Long Nylon Spacer - AndyMark, Inc