1. Dan Davidson, San Diego CA 2. Callaway uPro Go from Dec 2010 thru Jun 2015. In addition to distance to the green, it provided distance to the hazards as well Golf Pad GPS app on Apple iPhone - Jul 2015 thru Jun 2019 18 Birdies app on Apply iPhone - July 2019 thru present 3. Currently using 18 Birdies app, cart GPS when available, my partners rangefinder info when he shares it and I always compare with the course tee markers and yardage markers. It is frustrating when they don't all agree. I would be happy to test the new technology and provide a detailed review.