1985 - 1999 Airguide 2025 Speedos. It’s not complicated to disassemble and pull the pressure-mechanical Innards out. and upgrade to GPS. 2012 - 2015  Gauges: Display The upgrade is directly applied at the Paddlewheel. Simply part the PW connector... Insert the NL4-NT  Inline between the PW connector halves. 1976 - 1984 Airguide 700 Speedos. It’s not complicated to disassemble and pull the pressure-mechanical Innards out. and upgrade to GPS. Nautic Laugic Call   360 901-4030 Nauticlaugic@gmail.com