All DCW "Flight Series" pedals are authentic, vintage-based recreations of classic designs. The Flight 250 is a recreation of the original DOD 250 circuit with all the vintage "grey box" specs you are looking for. The original 250 circuit has been tweaked through the years, but the Flight 250 is a hand built replication of that discontinued original box from the 70's that so many fell in love with. Some of the yellow reissues and later boxes moved to a 4558 dual op amp chip, while the original boxes used a single op amp 741 chip. Some other part values in the later units were tweaked to try to regain the character of the original unit while using the new chip, but the difference is noticeable. The Flight 250 uses the original 741 chip and the original circuit design. The only changes that have been made from the original unit is that the pedal has been made true bypass (which makes NO change to the actual tone of the pedal, but does improve the bypassed tone while the pedal is turned off), the power connection is now a standard Boss style center negative 9V barrel connection (No battery connection), and a status LED has been added for ease of use.