Pictures show the original HE123-EX which uses ATO fuses. The HE123-EX2 is identical but uses mini automotive fuses in line with the change in the HE123Mk2 which changed to mini fuses.
-RJ45 connector to 4 channels fused pixel outputs -mates with HE123RJ -can be used for as a breakout to power unfused pixel outputs like on rPi-28D or J1Sys P2
-Heavy duty 30A (maximum) rated power input connector -4 mini fuses (supplied with 4 x 7.5A). Maximum of 10A per fuse/output connector.
-pixel connection is made from a pixel board to the HE123-EX via RJ45 patch cable.
A standard patch cable is used for connecting between HE123-RJ and HE123-EX.
To connect from other pixel boards then a patch cable with 1 RJ45 connector on 1 end and stripped wires on the other end should be used.
The HE123 series manual is available here