Type A: 3500W concave. eleven files. Button + knob control, 2 cooling fans, stainless-steel + ABS flame retardant bottom shell Type B: 3500W (overclocking 3800W) concave, eleven gears, button + knob control, three cooling fans, panel backside case chrome steel Type C: 4200W (overclocking 4500W) concave, 11 gears, button + knob control, three cooling fans, panel bottom case chrome steel Type D: 3500W plane, 11 gears, dual knob control, 2 cooling fans, panel stainless steel + backside case ABS flame retardant Type E: 3500W (overclocking 3800W) plane, 10 gears, button + knob control, three cooling fans, panel backside case stainless-steel Type F: 4200W (overclocking 4500W) plane, 10 gears, button + knob control, 3 cooling fans, panel backside case chrome steel