This Lens Collar by Kirk is made specifically for the Nikon AF-S NIKKOR 70-200mm f/4G ED VR and AF-S NIKKOR 300mm f/4E PF ED VR lenses. Constructed from strong but lightweight aluminum alloy, the base is compatible with any Arca-style quick release clamp. Two safety screws prevent it from sliding out of an open channel clamp, and the locking knob secures the collar to your lens. It also has a 1/4"-20 thread so you can attach a different quick release plate to match your tripod or monopod head. An accessory hole is located on the plate and allows you to attach any of Kirk's flash brackets to the lens collar. The collar provides two points of support for your lens, adding stability and security.