Four different interchangeable mic elements are available, each with it's own pickup pattern. This interchangeable Sub-Cardioid mic element fits the AT853, AT933 and AT943 Premium Cardioid and Premium Slimline microphones. Note for owners of the Premium Slimline (AT943 and AT933) microphones: The Hyper-cardioid, Sub-Cardioid, Cardioid and Omnidirectional elements of this series also need the adapter (part# AT-ADAPT) to fit on the Premium Slimline (AT943 and AT933) mics. Note: Remember to order two elements if you want a stereo set. Here is a .pdf file with more information.