Tripod Mount Ring Lens Collar Compatible with Tamron 100-400mm f/4.5-6.3 Di VC USD (A035), Lens Support Bracket Holder, Bottom is Arca-Swiss Fit Quick Release Plate for Tripod Ball Head

A perfect for my Tamron 100-400mm lens. The tripod mounting works and fits perfectly. The price was really great.

The tripod mount is perfect. It fits the 100-400 lens exactly and is very secure. At one-third the price of the Tamron lens collar it's a great value.

Pretty much does what it says. The tripod ring latches on and the screw securely holds it on, and is pretty sturdy--no rotation or movement when it's tight. The foot has a few screw points, which work well, although theThe main issue I have is with the design, which I've removed a star for. I use the ring as a handle to hold the camera when it is not being used on a tripod, and in order to save space I turn the collar 90° so the foot is on the same side as the grip. Because the foot is vertical on this model, unlike how the foot is angled forward on the OEM Tamron part, the back of the foot and its sharp edges make it hard to hold the camera grip without catching fingers on the edge. To solve this, I rotated it to be 45° from horizontal/vertical, so the foot is pointing down and to the right when looking through the camera.One other annoyance is that the preinstalled screws on the bottom of the foot are very difficult to remove with the included allen wrench, but I use a plate which doesn't use that area of the foot so that is less of an issue for me.