A small but powerful synth which also has an arpeggiator and effects including delay and reverb. The main attraction is that you can add the custom oscillators and effects created for other Korg synths such as the Minilogue.
You build it yourself but I believe it's very straightforward assembly with no soldering.
The RRP for this is £100 but I've regularly seen it for £85 and just about resisted buying it. This reduction to below £80 was the last straw for my willpower.