The joints of an Indexing LiteMount are made up of two indexed/hirth clamps. Each half of the joint is a clamp with a slot for a tube to be inserted, and the two halves can be for different dimensions as the 'teeth' fit together the same. The different dimensions simply refer to the size of tube they connect to.
Each complete indexing joint must consist of both an Insert half and non-insert half, as a bolt runs all the way through the two clamps to tighten the joint together.. The non-insert half has the larger bolt hole for the head of the securing bolt while the insert half contains the threaded insert for the threaded end of the bolt to fasten into. As mentioned, the insert and non-insert halves of the joint can be for two different tube dimensions.