The Dual Frog Juicer can be configured for use as an automatic polarity reverser for two frogs, a reversing loop, a turntable, a wye, or a crossing. It uses the same basic design as the hex frog juicer but has 33 Amp transistors so it can be used with multi headed trains and 10 Amp boosters. Setup is simple, connect the input to the DCC track bus, and connect the output wires either to two frogs or two rails. A jumper controls whether the two outputs act as a pair (i.e. an auto-reverser) or independently (i.e. a pair of frog juicers). Another pair of jumpers controls the current set point for switching, either 2 Amps or 4 Amps. When used for frogs or crossings generally 2 Amps work best and for an auto-reversing application, 4 Amps generally works best. Does not work on DC layouts, DCC only.
See here for full details https://www.tamvalleydepot.com/images/Dual_Frog_Juicer_Manual_v2.1.pdf