>>Get maximum eye relief with the versatile ring placement of a one piece rail. >>The Leupold Backcountry cross-slot scope base is a strong and lightweight 7075-T6 Aluminium Picatinny rail. It’s constructed from 7075 aircraft grade aluminium which provides extra strength for heavier optics. The universal cross-slot design fits both picatinny and weaver style rings. Locking screws with Nylok won’t back out under recoil or vibration. >>Combine with Leupold BackCountry Cross-Slot Rings or Mark 4 Aluminium rings for a complete lightweight and rugged mounting solution.