Aluminum Spacer 1/2" OD x 1/4" ID x Many Lengths Round by Metal Spacers Online (7/16" Length, 50)
Brand: MetalSpacersOnline.com

All aluminum spacers have chamfers on both ends and have an acid washed finish that is compatible with anodizing and welding.

Outside diameter: 1/2"/12.7mm
Inside diameter: 1/4"/6.52mm (fits 1/4" or M6 bolts)
Length: Varies-Choose Length
Shape: Round
Material Type: T-6061 Aluminum with tumbled aluminum finish