Date: April 18, 2026 Subject: Analysis of control files for the Estim 2B electro-stimulation device 1. Introduction The Estim Systems 2B is a popular, high-end power box for erotic electro-stimulation (e-stim). It supports external audio input, allowing users to load audio files that create specific stimulation patterns. These are commonly referred to as “2B files” in user communities. This report clarifies the actual file types, their encoding, safe usage, and how to create or source them. 2. Supported File Types The 2B does not use proprietary file extensions (e.g., .2b ). Instead, it accepts standard audio files via the stereo 3.5mm audio input (Link mode) or USB audio (with a compatible PC). The device treats the left and right channels independently.