The Washer,6.5x20x1.6 is the most widely applied product in the KZ1000C4 POLICE 1000 1981 USA CANADA TAILIGHT ('79-'81 C2/C3/C4) ( five times ).
A sample from the products for the Tailight ('79-'81 C2/c3/c4) include: Lens,tail Lamp, Bolt 6x20, Bulb,12v 32/3cp, Body-comp-tail Lamp.