According to QRP Labs, the number of QCX monoband 5W CW transceiver kits sold has passed the 4,000 mark.

The QCX transceiver is a single-band 5W CW transceiver kit, with WSPR beacon and built-in alignment/test equipment. Available for 80, 60, 40, 30, 20 or 17m bands. It has rotary encoder synthesised tuning, VFO A/B/Split, Iambic keyer, CW decoder, and more. $49 US but does not include an enclosure.