This is a great accessory for precisely collimating your Newtonian reflector telescope to achieve the best image the telescope can deliver, especially for faster systems (f/5 or lower).
It’s very easy to use, simply insert the laser collimator into the 1.25″ or a 2″ focuser. Coming next to adjust the secondary mirror, the red dot of the laser hits the center of the primary mirror then tilt the primary mirror so that the return red dot hits the target on the laser collimator. But please check for both high and low focuser positions to make sure the red dot stay at the same place.
The collimator is made of strong anodized aluminum and requires three LR44 type batteries.