If you like the lightweight nature of red dot sights but want a bit of zoom, the 2x40 Fixed Power Red/Green Dot Sight from Delta Armory will provide. This red/green dot sight offers a choice of reticle colours and 5 brightness levels for a good view of the ringed dot reticle in any ambient lighting conditions. 
With an integral 20mm Picatinny rail mount, full adjustment for windage and elevation via capped adjustment turrets and generous eye relief, the 2x40 Fixed Power is ideal for those who use an Airsoft assault rifle or SMG and want a better view of their targets at long range!
 
Features
Aluminium construction - Steel mounting bolt, glass lenses
Integral 20mm Picatinny rail mount - Ready to mount on 20mm rails
Low profile design - Minimal height over bore, may require a rail riser for M4/AR-15s 
2 x Magnification - A red dot sight with a bit of zoom
Red/Green reticle colour options - Switch between depending on the environment
5 Brightness settings for each colour - Use less for low light and more for bright light
Windage and elevation adjustable - Zero to perfection for improved first-shot hit probability 
Capped adjustment turrets - Unscrew the cap and use a flathead screwdriver to adjust
Long eye relief - Great for forward mounting, provides a clear view even when your eye is far from the optic
Flip-up lens caps included - They look cool and keep your lenses clean!
Battery compartment inside the illumination adjustment dial - Unscrew the top cap to access
Battery: 1x CR2032 3V Button Cell (Included)