Simple thumb screw knob, upgrade to 180 degree quick lock knob. The quick lock device is made of stainless steel, which can be locked or released by rotating 180 degrees and unlocked by pulling the knob. The connecting shaft of the tripod ring is changed from hollow to solid core, the ring body is thickened, and the inner wall is covered with PVC film to protect the lens. The bottom plate adopts -SWISS structure, and the non- screws are detachable. The length of the plate is about 70mm, and 1/4 and 3/8 screw holes are reserved at the bottom. Compatible with 50-400mm F/4.5-6.3 Di III VXD A067. Type: Lens tripod ring Model: IS-TA5040 Applicable models: For 50-400mm F/4.5-6.3 Di III VXD A067 Material: Metal colour: black Package Contents: 1 x Lens Ring Bracket Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.