Sako Optilock Bases for A7 PICATINNY, BLUOPTILOCK™ scope mount rings and bases are precisely machined out of solid steel to ensure perfect mating with our integral receiver scope mount rails or Weaver (Picatinny) rails and optimal scope alignment. OPTILOCK™ scope mount bases come clamshell-packed in pairs. All the parts required for assembling bases to receiver and rings to bases are included (plus hex key).OPTILOCK™ scope mount bases are available in three configurations for Sako rifles and one configuration for Tikka and Sako TRG rifles and one configuration for Weaver (Picatinny) rails. All configurations also available in stainless steel, Weaver model also in phospatized configuration. Choice of appropriate Sako base depends on action length, scope tube length and required eye-relief. Sako S180R916 SS Short Action Weaver-Picatinny Base