The Element Delta type red dot sight is a great value optic. There is no magnification so it would really be for short range snap shooting.
We found that the adjustable brightness settings are limited to about 5 which are selected by a push button on the left side. This also powers the unit on/off by pressing for a couple of seconds.
Will fit all standard rails and is quite well made and looks great but if you want a better quality optic then you would probably be better looking at a more expensive unit.
Please note that these are for Airsoft use only and you may wish to fit appropriate lens protection covers to avoid damage.