Zinc plated replacement Accu-lube dust cap for Boat or Utility trailers. This dust cap is used if your axle is an Accu-lube axle with a grease fitting on the tip of the spindle. Rubber plug easily removes to access your grease fitting this dust cap measures 2.441 inch across and will fit most 6 Lug trailer hubs. Drive in installation ensures a tight fitment in your hub.