It may look like a toy but the Teenage Engineering OP-1 certainly defies its appearance. This compact, mobile synth is solid. The sounds are amazing. You'll have so much fun...we did! The OP-1 comes with eight unique synthesizer engines and eight quick selection keys for instant access. Tweak your sounds in real time and record everything to tape. All sounds are made up from the Engine, ADSR envelope, a dedicated Effect and a selection of LFOs. All elements are fully exchangeable.