Straight adapters create an extension between two mating joints. The length in the middle is by default 1.5x the length of the joint, so a 24/40 extension would be 60mm in the center, and 40mm for each joint so would be 140mm total. For non standard lengths you can simply enter the length needed into the comments/notes area when you checkout. Or for different sizes of joints not listed call or email us for a custom quote.
Joint sizes are always the same size M/F combination with straight-extension adapters.