About the AP-640 Replacement Lens Foot The AP-640 replaces the stock foot on Sony Lenses (See list below, Image of compatibility chart, or our website). The AP-640 is precision machined to slide right into an Arca-Swiss style quick-release clamp. It also has 1/4" and 3/8" tapped holes for mounting to non-quick-release tripod heads and monopods. All replacement feet feature the same dual safety stops and flash bracket compatibility as our lens plates. For use on the following Lenses: Sony 400-800 f/6.3-8 G OSS Lenses What's Included AP-640 Arca-Swiss Style replacement lens foot (Qty 1 Mounting Screws – M3 x 6mm Socket Head Cap Screw (Qty 4) Safety Stop Screws - M3 x 6mm Socket Head Cap Screw (Qty 2) Hex Key – 2.5mm (Qty 1) Not compatible with most Manfrotto or Gitzo clamps. Only use high quality QD swivels from reputable brands.