Genuine Brocock Airguns picatinny side rails.

The Brocock Picatinny Dual Side Rail attaches to the factory Brocock picatinny scope rail and leaves you with an additional Picatinny rail on each side of the rifle. This tactical upgrade gives the rifle added function for accessories while adding to the tactical appearance of the Brocock rifle.

Will only fit to the picatinny rail as shown here.

As long as you have the Picatinny main scope rail it will fit the following models:
Compatto, Bantam, Compatto MK2, Bantam MK2, inc sniper and HR models, Concept Lite, Commander, Patagonia, Magnum (including XR models), Atomic XR, Ranger XR