Sena Earmuff Cradle The Sena Earmuff Cradle is designed to transform Sena 20S, 20S Evo, 30K, or 50S units into an over-the-head earmuff style headset, eliminating the need for a helmet. It's ideal for sideline communication with riders or drivers, be it for coaching, instructing, media production, or coordinating pit crew activities. Features: Compatible with Sena 20S, 20S Evo, 30k, and 50S communication units (each sold separately) Converts the existing Sena unit headset to over-the-head earmuff cradle Detachable microphone Perfect for coaches, riding instructors, UTV riders, media production, commercial industries and pit crews Over-the-Head Sound: Noise reduction rating: 28 dB Signal to noise ratio: 34 dB Sound level conversion: 33 dB