What input signal does this SCR controller require

While it fits dozens of 50BT and 38-series models

including a durable piston assembly

Does this gauge valve include the sight glass and guard rods

Maxitrol AD1094C-1050 Amplifier and Selector Freon What input signal does thisThe Maxitrol AD1094C 1050 is a high performance Series 94 amplifier and selector designed for precise temperature control in direct fired gas heating systems. Engineered to maintain stable atmospheric conditions, this unit features a wide setpoint range of 100 to 500 degrees Fahrenheit, making it a staple for industrial makeup air and process heating applications. As a critical component of the Selectra electronic gas modulation system, the AD1094C