Comparison : Item # 7531-0187, Delrin® 150 Black Round Bar
Item # 7531-0250, Delrin® 150 Black Round Bar
Item # 7531-0312, Delrin® 150 Black Round Bar
Item # 7531-0375, Delrin® 150 Black Round Bar
Item # 7531-0437, Delrin® 150 Black Round Bar