Features: Metal tripod mount ring stand replacement base foot for RF 600mm F/11 IS for STM & RF 800mm F/11 IS for STM telephoto lenses, support vertical shooting. Designed with two bottom quick release plates, both are RRS/ARCA-SWISS standard. Made of aviation aluminum, CNC precision machining, hollow weight reduction design, polishing and surface anodizing treatment, beautiful appearance and fine workmanship. One end of the bottom plate is locked with spring screws, and 1/4 screw holes and 3/8 screw holes are reserved; the other end of the floating plate is reserved for 1/4 screw holes. Quick release plate is AS 39mm standard, for RRS / ARCA-SWISS / KIRK / WIMBERLEY / MARKINS / SUNWAYFOTO / KANGRINPOCHE / BENRO /MARSACE / ISHOOT ball for head of Arca 39mm fit. Specifications: Material: Aluminum Alloy Colour: Black Size: Approx. 90x38.5x38.5 mm/3.54x1.52x1.52 inch Screw Hole: 1/4 & 3/8 Screw Holes Applicable Model: for RF 600mm F/11 IS for STM & RF 800mm F/11 IS for STM Telephoto Lenses Note: Please allow 0-1cm error due to manual measurement. pls make sure you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 1x IS-THRF680PRO Lens Collar Support Base