Elkadart Dart Accessory: O-Ring Applicator Tool with 10 2BA Rubber O-Rings/Washers (Steel and Soft Tip Darts) Rubber dart washers, also known as o-rings, are an often overlooked piece of dart equipment, yet they are truly invaluable Washers help prevent the loosening of metal or alloy shafts by tightly securing the shaft against the barrel Using the Elkadart applicator, simply slide a rubber dart washer over the threads on your dart shaft Compatible with both steel and soft tip darts; An essential accessory for causal and competitive dart players alike Includes 1 applicator tool and 10 2BA (3/16") sized rubber dart washers/o-rings