A tad bit longer would be ideal - Vortex 45 Degree Red Dot Sight Mount

This product is solid and seems high quality. I wish it had two more rails on it, but I think I will get by with it as is. I mounted a Burris RT-5 on it, and it's a bit short for that, one edge of the Burris mount only grabs about half a rail. So I would not recommend this for an optic unless it's something short, like a simple red-dot, or maybe a smaller magnifying optic (I think the Burris RT-3 mount is likely shorter). Also, be aware that the screw is a Torx-type (star head) and fairly small, so you will need to have that tool to mount this. I'm not sure what size Torx head it is, but I think it is a T10 or smaller.