The battery might be discharged, replace battery.
The battery might not be installed correctly, please see user manual for installation instructions.
The battery is not making contact, clean contact surfaces and reinstall battery.
Has the battery cap been tightened enough? If you're not sure, you should tighten the cap and try again. Read more>>
The switch button is defective, check our repair policy.
When the sight comes out from the factory, the dot is has been centered in the sight. Normally this means that only small adjustments are necessary, providing that the weapon rail is properly aligned.
Do not continue to adjust windage and elevation mechanisms if you encounter resistance; instead check alignment of the rail (or carry handle) to the barrel.
If the impact point is moving, check the mount and the weapon rail’s (or carry handle) stability.
If you still cannot zero your sight, check our repair policy.
If the dot does not appear to be perfectly round, this is probably caused by the way that your eye perceives the dot, rather than by some mechanical defect. Due to differences in individuals' eyes, round objects that subtend areas near 3 minutes-of-angle (MOA) may appear in a variety of shapes depending on the individual and other environmental influences. Inexpensive red dot sights sometimes have manufacturing defects that can cause the dot to be an odd shape.
A simple test that can be easily performed will allow you to determine the cause of the perceived variation:
This effect is less pronounced in sights with larger dots. A bigger dot appears to the human eye to be more round than a small dot. The Diode dot is round, when mounted into the sight, but might appear not to be round due to the condition of the human eye. More people will see the dot in a sight with a 10 minute-of-angle dot as being perfectly round than will be able to see a 3 MOA dot as round. The smaller the dot, the more people will experience it as not round