TAG - Drop Down Adapter (1" Drop)The options in the drop down menu are telling you exactly what joint size type is on the adapter. For example: 1. "Double Female 10 14MM" This literally means there is (1) 10MM Female and (1) 14MM Female fitting 2. "14MM (Female) to 18MM (Male)" This literally means there is (1) 14MM Female and (1) 18MM Male fitting Common scenario. 1. You want to buy a drop down adapter that keeps your rigs original joint type the same. So if your rig is a 14MM