1, Reversing relay module. Powers any reversing motor equipment, can be used for any application that requires the ability to reverse motion. 
2, Support Momentary-action(Self-resetting) switch and Alternate-action (Self-holding) switch. For Self-resetting switch, when the switch is pressed the motor operates, and when the switch is released the motor stops.
3, High quality aluminum enclosure, thickness 1.5mm/0.06". Diameter M6 / 6mm threaded copper terminals for power supply and load. Connect switch terminal block: pitch 5.0mm/0.197", wire size 26~12 AWG / 2.5mm square, stripping length 7mm/0.28", Metric M2.5 slotted screw.
4, Power on indicating red LED. Forward and Reverse status indicating LED, forward status lighting red, reverse lighting green.
5, Operating Voltage: 20 ~ 30V DC, Rated current 50 Amp.

July-7-2021, from version 1.0 change to 2.0:
Changed the output action status. Exchanged the positive and negative positions of the power supply. Please download and read the datasheet for specific details
Datasheet: 
https://www.czh-labs.com/tmp/madeimg/datasheet/F-1021-ver2.pdf
https://www.czh-labs.com/tmp/madeimg/datasheet/f-1021.pdf