Shop › B5 SIERRA K STOCK FLAT DARK EARTH B5 SIERRA K STOCK FLAT DARK EARTH $57.95 B5 Systems Sierra K Receiver Extension, Fits B5 Systems Sierra Extension, Flat Dark Earth SRK-1656 Quantity: Add To Cart Added! B5 Systems Sierra K Receiver Extension, Fits B5 Systems Sierra Extension, Flat Dark Earth SRK-1656