Primary Arms Lower 1/3 Cowitness Microdot Base Mount/Riser LOWER 1/3RD COWITNESS: This lower 1/3rd co-witness microdot riser can be used to place the red dot in the bottom part of the scope tube for a less obstructed view. COMPATIBILITY: The microdot riser is compatible on in-line stock and similar platforms when combined with any Primary Arms or standard microdot designs. RUGGED AND DURABLE: Constructed of aluminum in hard-coat matte black anodized finish for corrosion protection. 3-YEAR WARRANTY: If a defect due to materials, workmanship, or normal wear and tear has caused your product to malfunction, Primary Arms will either repair or replace it.