Replacement 2-wire low voltage relay for Touch-Plate systems installed between 1946-1985 Designed as a compatible replacement for the following Touch-Plate models: 1550-A, 1550-B, 2500-B, and 4000 Rating is 120/277VAC 20Amp 1.0HP 125VAC, 1.5HP 250VAC Max Operating temp of 65°C The 20 Amp 3000 relay is a mechanically latching relay utilizing “Contact Closure” low- voltage switch technology. The relay only switches directly ON/OFF, this feature is technically known as “Single Pole, Single Throw” (SPST). This relay only works with a Touchplate System which is a 2-wire system. It will NOT work with a 3-Wire system like GE or Remcon.