The 55mm dual tension ballhead has become increasingly popular since launching. This ballhead fatures dual adjustment having a large knob for coarse adjustment and a smaller knob for fine adjustment. This really allows the user to get the ballhead dialed in for their needs of shooting and shooting style. Specifications for Two Vets Tripods Inc 55MM Dual Tension Arca: Manufacturer: Two Vets Tripods Inc Color: Black Weight: 1 lb Condition: New Package Contents: Two Vets Tripods Inc 55MM Dual Tension Arca