Color/Finish -- Any -- Black Black Chrome Blued Bronze Dark Earth Desert Tan Green Grey Matte Black Matte Chrome NiB-X Nickel Pink Stainless Steel Tan Two Tone Barrel Length -- Any -- 10 10.5 11.5 12 13 16 16 1/4 16.125 16.25 16.5 16.625 17.2 18 18" 18.25 18.5 18.5 & 28 18.5/28 20 21 24 26 28 28.7 3 3.125 3.13 3.18 3.2 3.20 3.4 3.9 30 4 4.1 4.25 4.52 4.68 4.75 4.9 4.96 5 5.11 5.5 6 7 7.5 8.5 9 Stock -- Any -- A2 Head Down M4 M4 Fixed MOE Black MOE Green MOE Tan Retractable Side Folding TAPCO Black Under Folding Youth