What GPS can I use with my ICOM VHF radio?

Icom does not recommend a specific manufacturer of GPS equipment. However, most GPS equipment that meets the NMEA 0183 standard, Version 2.0 or better, will work with ICOM VHF radios. This NMEA standard uses the following 3-letter sentences: 

GGA= Essential fix data with 3D location and accuracy (preferred sentence) 
This includes Lat / Long, fix quality, number of satellites, horizontal dilution of position, altitude above sea level, height of geoid (mean sea level), time in seconds since last DGPS update, DGPS ID, and checksum data. 

GLL= Geographic position, Lat / Long 
This includes Lat / Long position, time of fix, data active or V (void) and checksum data. 

RMC= NMEA recommended minimum 
This includes time of fix, active or void, Lat / Long, speed over ground, track angle, date, magnetic variation, and checksum data.