Special Mine Services manufactures a line of connectors used in the Entertainment Industry - all CSA and UL listed. All connectors are interchangeable with other manufacturers, a strategic advantage our product has over our competitors - the ease with which they go together. The assembly process is the same on all styles from different manufactures. When the sleeve is pulled over the contact, one simply aligns the hole in the rubber sleeve with the hole in the contacts, Then, insert a phenolic retaining pin. The hole through the rubber sleeve is significantly smaller than the pin thereby creating a water-tight fit between the two parts.