Bottom is 39mm Arca-Swiss standard plate, for / ARCA-SWISS tripod for head clamp of 39mm fit, suitable for IS-JZ30, IS-JZ50, IS-JZ64, IS-QJ58 and more. Inner wall of the tripod is irregular in structure, and hole is reserved, which does not affect the use of on the lens, the tripod cannot be rotated, and only supports horizontal aviation aluminum machining, lightweight hollow polished and anodized finish exquisite workmanship and for long service life. Plate length is about 50mm, built-in standard plate for tripod for head, equipped with 1/4" and 3/8" screw holes, and stainless-steel screws, allows you to fix the lens to the tripod directly. Lens collar support is specially designed for 100-400mm f/5.6-8 IS lens.