Cylinder is original color(silver), we won't sell black cylinder any more. We have tested well the valve before shipping, so you'd better not adjust or disassemble valve at will. To install them, you only need to keep the original barrel, grip & trigger set, and probe It can be shot about more than 20~50 times.(Due to constant pressure, spring size and length of cylinder). Contact us for installation instructions when you get it. The valve is sealed by high pressure, it won't leak when the pressure up to 3~4MPa Don't care about the spare accessory package until maintenance is needed. We also have band, breech, shoulder stock, you can find them from our store.