Over the years, Ten Tec has released a surprising number of CW (continuous wave or Morse Code) Keyers for Amateur Radio use. There have been two basic designs, single paddle and double or imabic paddle models. Released in about 1975, the Model 670 is a single paddle version, intended for use with the Century 21 CW transceiver.
I look at Ebay from time-to-time, and lately I’ve been having a little too much fun. A Ten Tec Century 21 CW Transceiver (model 570) attracted my attention recently. The “570” was a solid-state radio intended for Novice hams and covered five bands: 80, 40, 20 (and with accessory crystals) 15 and 10 meters.