DSI® is replacing the existing fiberglass yoke (31), DSI® Part Number 520-060, with a new yoke, DSI® Part Number 520-117 (no price change). The new yoke is made of a durable black polyurethane, molded around a stainless steel core, and is slightly heavier than the fiberglass. This yoke will become standard equipment on all SuperLite® 17 A/B & MK 21 helmets produced as of June 15, 1999.
The new yoke is fully retrofittable with the fiberglass unit it replaces and is readily retrofittable to all SL-17 A/B helmets. The only difference is that the three stainless washers, (DSI® Part Number 530-530 - location number 30 on the exploded view), used on the fiberglass yoke hinge installation are not used on the polyurethane yoke hinge installation.