Correct cant on your rifle is critical for accurate shooting on medium and long distances. Even slight cant deviations of your rifle will change your point of impact of each shot. This effect is even more magnified by the hop up which will cause the BBs to fly left or right depending on the position of your rifle.
Minimalistic design, durable construction and negligible weight makes this level a valuable tool that will help you to improve your sniping skills without slowing you down.
How to mount and align the bubble level:
The easiest way to mount the level properly without additional tools is to align the reticle of your scope with an object that is already leveled with the ground.
An example would be a window, a wall or a door of a house. Simply align the reticle with the edge of the window and manually adjust the level until the bubble is perfectly in the center. Then tighten the screws equally on both sides and you are done.