The Kirk LP-41 Lens Plate is designed to connect to the tripod foot of the Canon Tripod Mount Ring B, which is used with the 100mm f/2.8 USM Macro, 180mm f/3.5L Macro & MP-E 65mm f/2.8 Macro, 300mm f/4 IS, 70-200mm f/2.8 IS & 100-400 f/4.5-5.6 IS lenses. It converts the collar to make it directly compatible with Arca-type quick release clamps, without the need for additional quick release plates.
Each plate comes complete with all the necessary hardware and tools to make the conversion.
LP-41 Arca-Type Quick Release Lens Plate/Foot
Installation Tools & Screws