Garmin varia, rdu - Garmin Radar Head Unit, Varia

I had problems syncing my RTL510 tail light with my Garmin 810 bike computer. I called Garmin support and they sent me a replacement tail light. Twice. I updated the RTL510 through Garmin Connect several times. Nothing really fixed the sporadic problems. I bought this RDU from Campsaver with a 20% off coupon. Received it faster than expected with free shipping. I turned on the RDU and RTL510 and they synced perfectly. Better yet, this combination doesn’t affect the 810 at all. No battery drain. The RDU display is much brighter and easier to see than the 810’s. I can go road riding again and feel safe!