Walker's GWPXSEM XCEL 100 Advanced Digital Muff 26 dB Over the Head Gray/Black PolymerThe Xcel 100 allows the wearer to select between four different listening modes: Universal, Speech Clarity, High Frequency, and Power Boost. The Sound Activated Compression and variable Dynamic Sound Suppression automatically adjusts compression time according to noise level intensity and duration instead of using conventional "fixed time" compression. The XCEL 100 also comes with programmable auto shut off, so forgetting to turn the muffs off and