The tremolo has become one of b.y.o.c.'s most popular kits through word of mouth. And with good reason....the difficulty of the build is low, it's simple to use, and it just sounds good. This kit is based on the EA(Electronics Austrailia) Tremolo. It's a great vintage sounding trem like you would find on an old Blackface Fender Amp. The amplitude modulation is done with transistors, so unlike most opto-coupler based trems, you don't get an "on/off" sound on slower speed settings and there is much less current draw. It's also a lot easier to build. And the LED status light blinks in time with the speed.