C Washers are manufactured with an open slot for the inner diameter, allowing the washer to be slipped in and out of the joint with loosening the joint - not completely unbolting it. Used in applications where assembly and disassembly are needed. Machined from solid bar, these washers are very thick - ranging from 1/4" all the way up to 7/16" thick. Slots are cut oversize for easy on and off, and are available from #10 through 1-1/4" bolts and shafts. Popular in MRO, Machinery, power Generation, Power Transmission, and anywhere an extra strong washer/spacer is required. Turned and milled from 12L14 Low Carbon Steel Bar, material is DFARS compliant. Case Hardened for extra strength, and Black Oxide Plated for both appearance and improved corrosion resistance. 100% Made in the USA.