Anti-reflective coatings combined with nitrogen purging and O-ring seals, ensure the unit is fog proof, shockproof and waterproof. The 1X Strikefire, which comes with a 2X magnifier, is designed to be parallax-free beyond 50 yards, and the dot correlates to 4 m.o.a. in size. Powering the unit is a single CR2 3-volt battery, which is included, and, depending on setting, provides upward of 8,000 hours of runtime, though the unit powers down after six hours of constant-on. Price: $229.