The MIN-Series is so named because they are generally referred to in the industry as Mini-Change connectors, or Mini connectors. MIN Size I encompasses the 2, 3, 4, 5, & the smaller 6 pole version (there are two sizes of the 6 pole connector. One is a size I and one is a size II). All of the size I variety are based on a 1" hex for the receptacle and a 7/8" thread for the plug. MIN Size II connectors include the larger 6 pole, and the 7 & 8 pole connectors. The size II are based on a 1.125" hex and a 1" thread for the plug.