Works well. I’ve been clearing out some old batteries the last couple weeks and every one that employed the lipo killer discharged batteries to less than 1V per pack.
Some “interested user” testing established that not one pack contained enough residual voltage to initiate combustion after the discharge process was completed. The test involved puncturing battery cells after discharge to see what night happen. Every discharged battery had all the cells punctured in attempts to induce a battery fire with zero negative results. 2S through 6S, 800mA to 13,000mA.