The 3x Delta Optical magnifier is one of the shortest and most compact. It can be mounted for instant change from 1x to 3x magnification. It is compatible with all red dot sights (by Delta and others) mounted at the absolute co-witness and lower 1/3 co-witness. It also works with holographic sights and 1x prism scopes: tool-free azimuth and diopter adjustment for precise image sharpness.