The ScoGlow was developed when my aging eyes had a harder time seeing the turret marks while shooting a Troop Line at a PRS Match. We were under a roof and the sun was bright outside. That contrast made it tough to see. The same can happen in a shoot house, a shipping container, or just early in the morning or late in the evening. Just place on your scope tube and point the light at the turret. It is magnetized so you shouldn't lose it and can freely point it where needed. 
 
The red light works perfectly for night hunting situations.
 
Comes with the ScoGlow clamp, bulbholder, and 3 lights (2 warm white lights and 1 red light). These lights last a long time if turned off in between uses. They work on small watch batteries so they can be replaced.