The phrase " " refers to high-fidelity sound files designed for the E-Stim Systems 2B

Even with the highest quality files, safety is paramount. Always: Start with the 2B knobs at . Use high-quality, conductive electrodes.

Here's a link to a HUGE library of audio e-stim files that. Endless stimming with an MK-312BT or 2B. Enjoy! ErosTek Blog Unveiling Secrets: E-Stim Systems 2B Answers