Leupold DeltaPoint Pro with AR Mount 177156 ANSI the multi fuel capability allows for Open Top the multi fuel capability allows for the use of a Streamlight SL B26® protected Li Ion USB rechargeable battery pack or two 3V CR123A lithium batteries for added flexibility MPN SKU COLOR FEATURES OPTION RAIL SIDE STOCKED ORIGIN LIB4_D_APX LODB GM TCI LIB4 D APX LODB GM OD Green Behind the Head Motorola APX None Left N US LIB4_D_APX RODB GM TCI LIB4 D APX RODB GM OD Green Behind the Head Motorola APX None Right N US LIB4_D_P53 LODB GM TCI LIB4 D P53 LODB GM OD Green Behind the Head Harris P53 None Left N US LIB4_D_P53 RODB GM TCI LIB4 D P53 RODB GM OD Green Behind the Head Harris P53 None Right N US LIB4_D_XXX LBK TCI LIB4 D XTS LBK Black Over the Head Comfort Fit Motorola XTS None Left N US LIB4_D_XXX LBK TCI LIB4 D P53 LBK Black Over the Head Comfort Fit Harris P53 None Left N US LIB4_D_XXX LBK TCI LIB4 D APX LBK Black Over the Head Comfort Fit Motorola APX None Left N US LIB4_D_XXX LBKB TCI LIB4 D APX LBKB Black Behind the Head Motorola APX None Left N US LIB4_D_XXX LBKU TCI LIB4 D APX LBKU Black Helmet Mount Motorola APX None Left N US LIB4_D_XXX LBKU TCI LIB4 D THR8 LBKU Black Behind the Head Tetra THR800 None Left N US LIB4_D_XXX LBKU### TCI LIB4 D APX LBKUW Black Helmet Mount Motorola APX Team Wendy Left N US LIB4_D_XXX LDE TCI LIB4 D XTS LDE Flat Dark Earth Over the Head Comfort Fit Motorola XTS None Left N US LIB4_D_XXX LDE TCI LIB4 D P53 LDE Flat Dark Earth Over the Head Comfort Fit Harris P53 None Left N US LIB4_D_XXX LDE TCI LIB4 D APX LDE Flat Dark Earth Over the Head Comfort Fit Motorola APX None Left N US LIB4_D_XXX LDEB TCI LIB4 D APX LDEB Flat Dark Earth Behind the Head Motorola APX None Left N US LIB4_D_XXX LDEU### TCI LIB4 D 329 LDEUW Flat Dark Earth Helmet Mount MBITR Whether it's topping your AR so you don't have to re zero after a battery change