This is the Nix Trainz Power Bridge III 2-wire stay-alive for any brand of decoder with 0.6F of capacitance. It is very compact and allows you to mount the two capacitors remotely where they will fit. Note; both capacitors need to be connected. The small circuit board 2.5mmH x 6mmW x 13mmL. Each capacitor is 4mm diameter by 12mm long.