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. 2008 - 2011 Gauges: Display The upgrade is directly applied at the Paddlewheel. Simply part the PW connector... Insert the NL4-NC Inline between the PW connector halves. Nautic Laugic Call 360 901-4030 Nauticlaugic@gmail.com