Good looks, strength and versatility. Weaver styling combined with the X-Lock's four-screws-per-base design gives you a rock solid foundation for your scope. Many people consider Weaver style bases one of the industry standards for hunting rifles. Made from high-quality aircraft grade alloy, these bases will work with most Weaver-style rings you want to mount on them. These bases are made to fit the X-Bolt with X-Lock only.