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, GNS 430W/530W, GNC 255A, GTN 650 AND GTN 750.
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). Is the Garmin 106A CDI - Vor / Loc / GS fully functional with a Garmin 420 WAAS?
A 106A CDI - Vor/Loc/GS will work with a GNC 420W GPS but you are limited to only GPS and WAAS approaches. You would not have Nav VOR, ILS or glide slope capabilities.