The EC20-DUSTCAP by Caplugs is a dust cap used to prevent dust, dirt, and other debris from entering electrical connectors. It is made of polypropylene, a durable and lightweight material. The dust cap has a ribbed outer surface for easy gripping, as well as ribs on the interior surface for a positive grip on the electrical connector. The ribbed design also makes the dust cap waterproof when it is firmly inserted onto the connector. This dust cap has a 20.9 millimeter inside diameter, and is transparent for easy visual inspection.