Vintage Bontempi Mini Polyphonic Synth Keyboard Basic Concertino 25. This is a cool little synthesizer featuring a 25 mini keyboard, 3 different instruments, a transposer, 3 volume settings. It’s in excellent condition and works well, just hold the select button and what you want to change. The boxes have various degrees of writing on them and will not match the picture shown as I have 9 of these. All the keyboards are in the same clean working condition.