1. The tripod mount ring is tailor-made and compatible with Sigma 18-35mm f/1.8 DC HSM Art Lens (Canon EF Mount, Nikon F Mount), can't be used for other lenses; only support horizontal shoot and cannot be rotated; | 2. The inner wall of the lens collar adopts a tilt design that fits the lens, and the joint adopts multi-point rubber pads. Unibody design, with anti-slip locking knob; the minimum bayonet is about 70mm, and the surface contacting the lens is affixed with 3M plastic film, preventing the lens from scratches; the width is about 12mm, and the net weight is about 120g; | 3. The tripod collar bottom is added 55mm long Arca fit quick release plate feature, can be used with 39mm Arca-swiss fit tripod ball head, panoramic head and clamp directly; more practical than lens collars without QR-Plate. Compatible with RRS / ARCA-SWISS / PMG / WIMBERLEY / MARKINS / PHOTOCLAM / SUNWAYFOTO / BENRO / SIRUI / MARSACE / ISHOOT ball head of Arca 39mm fit, suitable for iShoot IS-JZ30 / IS-JZ50 / IS-JZ64 / IS-QJ58 / IS-QJ64-FD / IS-JZ60BK / IS-JZ70MFT / IS-JZ80BK; | 4. The tripod collar using laser scanning technology to accurately obtain lens parameters, and then accurately carve out the shape of the inner diameter of the tripod ring according to the data. The Lens support bottom reserved 1/4" and 3/8" screw holes and stainless-steel anti-slip screws for fixing lens to tripod directly; | 5. The tripod ring is made of Aviation Aluminum, precisely machined by world-class high-end CNC turning center, hollowed-out work processed by Multi-Diamond Cutter finely, polished and surface anodized finish, lightweight and solid. The appearance and exquisite workmanship are much better than similar products made by mold.