This is a good quality CW practice oscillator. It uses a different chip and circuit than the orginial SPO-1. This offers a smoother / louder control of the volume, a better tone quality and more stable frequency over the full volume range.
A great choice for anyone undertaking a construction project as part of a Ham Radio training course. The kit is complete with a 50mm loudspeaker, Volume control & all parts including high Quality PCB.