Then there's new Aimpoint PRO (Patrol Rifle Optic). The PRO splits the difference between the M2 and M3 with 3 years of battery life on the same 7 of 10 brightness setting, on the same 1/3N battery. The PRO is NVD compatible, and waterproofed exactly the same as the M2 and M3. In fact, it's supplied with M3 manuals, and just an addendum sticker inside the lid of the box detailing the PRO's features. The PRO comes with Aimpoint's QRP2 flat top mount for the price of an M2 or C3 without a mount ($85 value). Right now Aimpoint only let's LE dealers sell the PRO, but they can sell them to anyone. You'll have to find an LE dealer, or order online. The PRO runs in the low $400s.