Monstrum Tactical 4x30 Ultra-Compact Rifle Scope with Illuminated Range Finder Reticle Ultra compact scope providing crystal clear targeting at 4x magnification, with a 30mm objective diameter and an eye relief of 2.5 inches Glass range finder reticle with range fnder markings for on-the-fly range estimation and long distance targeting, in both red and green illumination with multiple brightness intensities, for clean sight picture regardless of lighting or environment Integrated rail mount fastens securely to any flat top Weaver or Picatinny rail equipped rifle, see through design allows for simulataneous use of low profile iron sights Only 6 inches in length and 12 ounces in weight, ultra lightweight and compact in design