The SunwayFoto DDC-60LR Lever-Release Clamp can be mounted onto ballheads or Arca-swiss, RRS, Kangrinpoche ballheads. Use Metric 6 flat head screw to mount onto a ballhead. It can mount onto 3/8 threaded post. The lever can be stopped in 3 positions, they are fully closed; half open; and, fully open. The half-open position allows the camera/lens plate to slide within the clamp for positioning adjustment.