This Pedal is currently available.
4-wire noise gate with key input
This Shut Up Noise (SUN) Noise Gate includes 4 jacks to wire the pedal in 3 or 4-wire method.
Wire it directly in front of the amp, or in the FX Loop, using the key input, for even more hum annihilation. There's a Low/High threshold switch inside the enclosure in case you miss some noise silencing power.
https://guptech.ca/products/copy-of-guul-noise-gate?variant=42020110827720