The GI 106A course deviation indicator (CDI) from Garmin features VOR/LOC/GS needle, rectilinear meter movement, resolver output for GPS interface, and internal GPS mode annunciation. Size: 3.25"W x 3.25"H x 4.625"D, weight: 1.4 lbs. Warranty is two years. The GI106A is designed for IFR installations. This product commonly used with the SL 30 and GNS 430W/530W.
GI 106 does not have a Back Course indication.
Can the Garmin GI 106A be used with a Garmin GNC 300?
Yes, you can use the 106A for GPS right/left indications. As the 300 does not give glideslope you may want to use a GI 102A (no GS indicator).