San Tan Tactical STT-15L, Stripped Lower Receiver, Multi Caliber, Anodized Finish, Olive Drab Green STT15L-LOWER-ANO-OD The STT-15L has all the same great aesthetics as SanTan's standard STT-15 Receiver Combo but incorporates a significant weight reduction. They set out to design the STT-15L for those who participate in 3-gun, hunting, or any other shooting activity where weight is a concern.