Sizing shown as Inside diameter x Outside diameter. Inside diameter stated is not the actual ID, it is the shaft it will fit over.
Copper flat washers are soft, malleable metal rings used to distribute fastener loads, protect surfaces from damage, and prevent loosening.
Because copper is highly conductive and heat-resistant, these washers are ideal for automotive engines, hydraulic fittings, plumbing, and electrical connections where reliable, leak-proof seals are required
