1. The lens collar is tailor made for Sigma MC-11 Mount Converter of Canon EF-E Mount, Can?t be used with SA-E Mount and other lenses; relying on the switch and bayonet to position, cannot rotate in the tripod ring; when shooting vertically, the MC11 adapter ring needs to be taken out and reinstalled; | 2. The edges and corners are polished, the inner wall is affixed with 3M plastic film, preventing lens from scratches; the shortest inner diameter of the lens holder is about 61.5mm, the maximum width of this contact surface is about 20mm; net weight is about 145g. 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; | 3. The tripod collar bottom is added 70mm 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. The Lens support bottom reserved 1/4" and 3/8" screw holes and stainless-steel anti-slip screw for fixing lens to tripod directly; | 4. This lens support bottom's dovetail groove is 39mm Arca-Swiss standard, 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; | 5. The tripod ring is made of high-density Aviation Aluminum, CNC precisely machined, hollow-out weight reduction design, hollowed-out work processed by Multi-Diamond Cutter finely. Polished and surface anodized finish. Lightweight and solid; precisely machined by world-class high-end CNC turning center; the appearance and exquisite workmanship are much better than similar products made by mold.