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 30mm maintube and is ideal for standard to magnum calibers. The PRW2 mounts are very popular since many rifles come with Weaver-style bases or cross-slot rails.