The Sennheiser SKM 300 G4-S is a mobile wireless microphone transmitter compatible with the EM 300-500 G4 wireless receiver. It is designed with and without interchangeable microphone capsules, so you can choose the one that best suits your application. The transmitter operates in a wide tuning range of 50 MHz UHF with 2000 selectable frequencies. It provides up to 8 hours of operation on two AA batteries, a transmission range of up to 100 meters, and a selectable 10/30/50mW RF power output to overcome interference in RF environments.
The durable, all-steel SKM 300 G4-S features a lockable, non-removable button to prevent modifications during performance.
Adjustable gain lets you set the right level for the sound. When the sync function of the receiver is enabled, the transmitter and receiver are quickly connected to the same infrared frequency. The backlit LCD screen displays important information and provides quick menu access.

The unit can be powered by two AA batteries or rechargeable batteries BA 2015 Accupack (sold separately). With the LA 2 charging adapter and the L 2015 quick charger (both sold separately), Accupack can be charged without removing it from the dispenser.
The transmitter's interchangeable capsule design allows you to use a wide variety of dynamic and condenser microphone capsules with polar patterns ranging from wide omnidirectional to narrow supercardioid - capsules include MMD 835, MMD 845, MME 865, MMD 935, MMD 9445.
Also, according to EW 300/500 buyers, the SKM 300 G4-S is also backwards compatible with all previous versions. You can mix and match G4 / G3 / G2 / G1 receivers or bodypacks, holders and pluggable transmitters. It is also compatible with the EW 100 system.