I have the HHA opimizer Lite. I started out with the battery on it but took it off. It was too bright, and plenty bright without the battery. The Impact Cosmic is good also and very bright. The thing I didn' t like was the size of the fiber optic was to big, it makes the dot brighter but hard for fine aiming. HHA also has a brand new Optimizer Lite site that similar to the Cosmic. It has 3 feet of fiber optics v.s. 2.5 feet in the Cosmic! Check it out!

Good Luck!!