First Strike Hero Carbon Fiber HPA Tank - 100/4500 - Black Tanks Are Not Compressed and Empty When Shipped & Sold 360 Degree Rotation  Multi-position brass thread collar enables custom set-up without sacrificing reliability, convenience, or adding length Brass Threads  In addition to rotation 360 degrees, the brass collar eliminates the excess wear and galling common with aluminum threads Pro Fill Nipple  Featuring an exclusive conical strut that increases life of the fill nipple o-ring and reduces maintenance Low Profile Design  Lowest profile regulator design in the market measuring just .75 from tank to ASA