most mosfets; reprogram the unit so it sees an off single as a single shot as well.
poor idea in practice though. Firstly, it's 2 shots per trigger pull, so technically it's not semi auto, it's 2rnd burst.
So you can't use it anywhere you'd be limited to semi-auto. Which leaves games that allow full auto.
And if you need to fire that fast in semi, you might as well be using full auto.
Otherwise, 2rnd burst is easily programmable in many mosfets.
neat technical idea, accomplished easily by reprogramming a mosfet, but entirely pointless.