Fortis F1 Optics Mount is designed to work in conjunction with Aimpoint s popular Micro H-1, or T-1 optics. The F1 Optics Mount is designed to attach to your flat top upper receiver. Its lightweight low-profile is one of the lightest designs out there at 1.1oz. The Fortis F1 Optics Mount features an innovative design by extending the optic forward for faster target acquisition. It secures to any MIL-STD-1913 Picatinny Rail with two slotted machine screws. Offering a lower 1/3 rd to your back up iron sights for a larger field of view. **Will work in conjunction with 3x magnifiers. Product Features One Piece Billet Design Slotted Screws Attachment Aircraft Grade 6061-T6 Aluminum Military Specification Type III Hard Coat Anodized Logo on both sides Light weight 1.1oz Lower 1/3 witness Made in the USA!