Double base hit. This is the proven two-piece design offered by Browning for many years. It has a totally proven record for precision, reliability, and strength. Plus they are low profile on your gun for a better look and for the advantages of mounting just a bit closer to the bore centerline. For some gun guys, this quality of base will be the only design that will ever be good enough.NOTE: These two-piece bases fit the BAR and the BLR due to compatible barrel contour and attachment configurations. Features:Browning scope bases are machined from solid steelDouble recoil shoulder design holds rings securely, even under magnum recoil Compatible only with certain Browning Scope Rings (available separately).