Brake clamps are required to fix the brakes to your wheelchair. They come in three different diameters to suit your frame tube width; 1", 1-1/8" and 1-1/4".
The Extended brake clamps extend the brakes 1-1/16" from the frame, (inside width from the seat tube to the brake body).
Make sure you choose your correct frame tube diameter.
Price is for a pair of clamps (for 2 brakes).