A Grounding box does not change the sound in terms of the underlying sonic character, it does not make the sound warmer or leaner, etc. What is does change is the sound in terms of resolution, space, decay, presence, etc.
Clef Audio Ground Zero grounding device plugs into your Hi-Fi or AV components spare RCA socket to reduce the noise floor of the system.
Telos Audio Design Grounding Noise Reducer (GNR) Mini 3.1 is an active box that generates low distortion ground reference voltage for your Hi-Fi.
Akiko Audio Ground Conditioner Castello is a stand-alone passive unit which forms a zero-reference for your Hi-Fi system.
Telos Audio Design 1.5M Grounding Cables with RCA, XLR, USB-A, USB-B, HDMI mini Spade, HDMI termination for the Grounding Noise Reducers.
Telos Audio Design Gold Series Grounding Cables with exclusive Anti-Vibration ring and optional plugs for Grounding Noise Reducers and GNR Mini.