Sig Sauer Sierra 3 4.5-14x50 BDX SFP 30mm Rifle Scope Disguised within the form factor of a traditional riflescope lies the power of the SIG SAUER BDX Ballistic Data Xchange. The SIERRA3BDX riflescope provides the hunter an illuminated auto-holdover dot on targets when coupled with a BDX capable KILO rangefinder. Featuring exceptional SpectraCoat lenses, LevelPlex digital anti-cant, and KinETHIC kinetic energy transfer indicator, the SIERRA3BDX is incredibly simple to use. Range a target, put the holdover dot on target, pull the trigger, impact. SIG SAUER’s BDX, just CONNECT THE DOT.