This Cockpit Mount Kit is designed to attach to a 1.0in (25.4mm) Horizontal Tube, as found on Catrike and some other direct steered trikes.
A 90 degree elbow tube allows you to rotate the attachment clamp up or down on the horizontal steering arm. The 5in (125mm) wide T Bar attaches to the other side of the elbow tube. You can rotate the T Bar around on the vertical part of the elbow in order to move the T bar in and out.
This Cockpit mount positions anywhere forward or back on the steering arm that you would like. Most people like their Cockpit Mount either close to their controls or further forward near the head tube. When the T Bar is close to the head tube, it will only move in a small arc as you steer. This is a good place for a mirror, because the mirror won't move very much as you turn.
By putting the right amount of tension on the clamps, you'll find it's very easy to move things around and find the ideal position for everything. Once you've determined your ideal position, just tighten the clamps to lock everything in place.
The T Bar is 7/8in diameter, so anything that's made to attach to a handlebar will be happy there. To attach a mirror inside the T Bar, simply remove one end cap and install the mirror as if it were on the end of a regular handlebar.
If you have a direct steered trike with a less than 1 inch horizontal steering arm (early Actionbent, for example), order the 7/8in (22.2mm) clamp.