Leupold PRW2, Rings, 34mm High, Matte Black 175860 Leupold Cross-Slot mounting systems feature Weaver-style rings that work with both Weaver or Picatinny rails with 1-piece and 2-piece bases available for many popular rifles. This model is designed to fit any riflescope with 34mm maintube and is ideal for standard to magnum calibers.