• 1. The ring tripod adopts original factory standard, the structure has been redesigned and improved, compatible with Tamron Tamron 50-400mm f/4.5-6.3 Di III VXD A067, not for other lenses • 2.The original simple hand screw knob is upgraded to 180° quick lock knob. The quick lock device is made of stainless steel and rotates 180° to lock or release, pull the knob to unlock. We have changed the connection axis of the tripod ring from hollow to medium, thicker the ring body and then attached the PVC film to the inner wall to protect the lens • 3. The bottom of the lens bracket collar has a 70mm long Arca Fit quick release plate for direct use with 39mm Arca Swiss Fit tripod ball head, panoramic head and clamp. More practical than lens support collars with no anticut • 4.On the bottom of the lens support collar there is 1/4" and 3/8" screw holes and stainless steel non-slip screws to secure the lens directly to the tripod • 5. Tripod socket can be combined with the clamp mount converter IS-3950PRO (sold separately) for use with Manfrotto water heads