Brand: Jiffy-tite
This rubber "plug" protects a 3000 Series Jiffy-tite Socket to keep out dirt and debris when disconnected. Sold individually.
Note: Jiffy-tite calls this a "plug" but it is really a cap that fits OVER the release collar on the 3000 Series socket. (This is different than the 5000 series where the plug actually IS a plug that fits INSIDE of the 5000 series socket.)