Help with component choice for EMS project (TENS 7000 output gating)

I want to use an ESP32 to switch a TENS 7000's two electrode output channels on/off with millisecond-precision timing. The plan is for the TENS unit to stay on and run at a fixed intensity the whole time, I just need to gate when the signal reaches the electrodes. Are there any specific components I should use for the switching? And any things I should be careful of when wiring it up? I want to make sure I'm being safe about this. Thanks!