Using high-density aviation aluminum, CNC automatic numerical control machine tool, diamond composite cutter head, hollow engraving and precision processing; using vibration polishing technology, the precision is 20% higher than manual grinding, and multiple , so that the color uniformity of the metal surface is increased by 10%. 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 pasted 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 90mm, and 1/4 and 3/8 screw holes are reserved at the bottom. Compatible with 150-500mm F5-6.7 Di III VXD A057. Type: Lens tripod ring Model: IS-TA1550 Colour:black Material:Metal 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 a little different from the real thing. The measurement allowed error is +/- 1-3cm.