Please read carefully.

The drop down menu has many options.

The order in which the sizes are written is very important.

For example:
14MM Male to 14MM Female
- Means this adapter physically has 1x 14MM Male and 1x 14MM Female joint
- The (1st Joint) 14MM Male joint connects to the pipe
- The (2nd Joint) 14MM Female joint is where you place your nail (in this example)

If you are ordering a 14MM Male to 14MM Female, this means your oil rig has a 14MM Female joint, so the 14MM Male joint (from adapter) can connect to it.