Sergey's custom MP-661K Blackbird Drozd adjustable full-auto electronic circuit board. This board allows to adjust round per minute (shots per minute) RPM parameter of your Blackbird or Bumblebee BB gun.
This board provides the best versatility ever: 400-600-800-1000-1200-1400-1600-1800-2000-2300-2700-3000-3300-3700-4000 RPM.
First button adjusts the number of shots in a firing series, second - firing rate, third - duration of solenoid impulse in milliseconds.
One push shows the current level, second, third etc. pushes adjust the parameter.
Using this board will enhance potential of your MP-661K BB gun and will just give a lot of fun!
Made in Izhevsk, Russia where Makarov and MP-661K are produced.