The Icarus Instruments EXTenna Switch is a small device installed in an aircraft that permits an existing VHF comm antenna to be used with any handheld VHF radio. This greatly extends the range and readability of battery powered handheld radios. The normal handheld radios "rubber ducky" antenna has very limited range when used inside an aircraft cockpit. The EXTenna Switch eliminates the need to install a dedicated backup VHF comm antenna which is both expensive and adds drag to the airframe.

The EXTSW-1 Extenna Switch mounts behind the instrument panel using two supplied 6-32 screws. The 3.5 mm jack on the EXTenna Switch extends through the panel to allow access using the supplied cable when needed. An included template simplifies the installation of the EXTSW-1 to serve as a guide for drilling the mounting holes.

The EXTSW-2 Extenna switch includes an adapter plate which allows users to mount the EXTenna Switch into a 2.25 inch instrument cutout. A 3.125 inch adapter plate may be used to install into a 3.125-inch hole.