To determine the model required for replacement, the following information is needed: upper or lower mounting, number of mounting holes (5 or 8), weight & position installed. Beacons installed on the rudder, example: Citations and Barons, require a 2.25lb. assembly. Top replacement on Gulfstream II & III require a 9072412 in conjunction with the optional 16 hole mounting plate, p/n 06-170618-00. Model 90724 Series is a self-contained LED anti-collision beacon. It's solid-state circuitry and LED light source obsolete the "old style" mechanical oscillating beacons as well as the Whelen 90044 Series quartz halogen flashing beacons. Benefits include no moving parts, no EMI/RFI, no inrush current spikes and crisp on off cycles. There are several models available to provide compatibility with existing mounting patterns and profiles, thus eliminating the need to alter the aircraft.