The only difference with the is the water resistant case. As the ferrous lever is moved by the mic diaphragm, the lever disturbs the magnet field. From the earliest days of outside broadcasting and recording, keeping the microphone dry has always been something of a challenge. The fourth generation evolution wireless series makes professional wireless technology even more simple, flexible and reliable. With the MD Sennheiser took a rather different approach. The 2 diagrams below illustrate the differences. It is a very comprehensive selection, to cover every possible application.