The team here at 3D HD gear really likes the RF Resistant Omni Mini-Boundary Microphones Miniature 202RW installation omnidirectional "button" style condenser boundary mics for use in teleconferencing or voice lift sound reinforcement. These microphones may also be used in surveillance, ambient recording or audio observation applications. Improved RF immunity to greatly reduce susceptibility to radio interference from GSM based cell phones, PDA/cell phones, cell phones with walkie-talkie capability and other similar devices.