Double Mast Clamp: Used to connect two mast pipes . Used with the RRS-1903 Tilt Mount to give more rigidity to your setup. This mast clamp should be placed 4 to 5 feet above the tilt mount to lock to two masts together. (As pictured)

Works with mast pipes up to 2 & 1/8 inch outside diameter.

Not required. Recommended for a better, more secure, rigid setup.