My recently acquired (Thanks UmarexUSA) Umaerx EBOS CO2 BB Machine Gun was just screaming for some add-ons and to be honest the first thing that I noticed was the open sights really needed upgrading. Luckily the rear sight is removable allowing you to mount just about any type of Red Dot Scope or sighting system you want, just make sure it is high enough to see up and over the front BB hopper.
I decided to go with an EOTech Styled Red-Green Dot Tactical Scope and I have to tell you this guns looks awesome with it installed!
I finished off the look with an unobtrusive Tactical Rail Mount Flashlight. All in all I think I spent about as much if not more on accessories for this gun as it is worth to buy :)