Like Mechanic688 said, they are variable voltage DC power supplies. If I remember correctly, Lamda manufactured equipment for Labs/Research industry. Home electronic buffs use these to supply power to test circuits when they are breadboarding (design stage) new circuits. But now they mostly use computer power supplies due to the numerous and varied voltage. Power supplies a pretty basic equipment, and marketable but you would have to scope them to make sure they produce a constant sine wave. Probably had good amount of copper in those.