The Sennheiser EW-D SK is a digital bodypack wireless transmitter compatible with EW-D wireless receivers. Lightweight and comfortable for performers and presenters to wear, the bodypack features a rugged, all-metal housing well suited for daily use on stage. The EW-D SK is equipped with a locking 3.5mm connector that accommodates the compatible lavalier or headset microphone of your choice, or an adapter cable for guitar and bass. With a remarkable 134 dB dynamic range on its input, it can handle a wide variety of sound sources, including loud vocalists and performers, connections to musical instruments, and even line-level signals from mixers, all without requiring any gain adjustment. The unit features a mute button that can be locked out and overridden from the receiver or a mobile device during a performance. It quickly pairs with the receiver via Bluetooth at a distance up to 120', at the press of a button. What's more, the EW-D SK utilizes an equidistant tuning grid that equally spaces 2240 frequencies across its wide 56 MHz bandwidth to prevent disruptive intermodulation issues that occur when multiple transmitters operate in confined spaces. The EW-D SK is remotely configured and controlled via Bluetooth from either the receiver or the Smart Assist App installed on your iOS/Android phone/tablet—within a 120' range. The transmitter provides up to 8 hours of operation on two AA batteries or 12 hours with a BA 70 lithium-ion rechargeable battery pack (available separately). The L70 USB dual-charging station (available separately) is required for the BA 70 batteries.