Leofoto Outdoors Lever-Release Rapid Lock Ball Head w/ Hybrid Clamp Arca/Picatinny Black. The head has a large knurled knob control to lock/unlock the ball and a redesigned lever-release dual clamp system for both the ARCA and Picatinny rails with adjustable clamping width. The large ergonomic ball locking knob has an inner dial which controls the tension or drag on the ball for precise adjustments. Specifications for Leofoto MG-40X Outdoors Lever-Release Rapid Lock Ball Head w/ Hybrid Clamp: Manufacturer: Leofoto Color: Black Attachment Type: Arca Features of Leofoto MG-40X Outdoors Lever-Release Rapid Lock Ball Head w/ Hybrid Clamp Aluminum CNC Machining Package Contents: Leofoto MG-40X Outdoors Lever-Release Rapid Lock Ball Head w/ Hybrid Clamp Leofoto MG-40X: MG-40X Outdoors Lever-Release Rapid Lock Ball Head w/ Hybrid Clamp Arca/Picatinny Black