Spacer Spacer Type Round For Screw Size 3/8 in Overall Length 2 1/2 in Inside Diameter 0.38 in Outside Diameter 0.75 in Retaining Rib Diameter Not Applicable Material Brass Finish Zinc Plated Pack Size Small Pack System of Measurement Inch Hex Width Not Applicable Color Silver Dimensional Standards ASTM B16 Hex Width Tolerance Not Applicable Inside Diameter Tolerance 0 to 0.01 in Outside Diameter Tolerance +/-0.005 in Overall Length Tolerance +/-0.005 in Rockwell Hardness B55