FlightScope has spent twenty years measuring what a golf ball does in the air, which makes it the most credible company in golf to attempt this particular trick. The i4 doesn't just tell you it's 163 yards; it applies real-time environmental data and ballistic calculation to tell you what that 163 actually plays as, given the air you're standing in. In principle that's the most useful thing a rangefinder could possibly do — temperature, altitude and wind move a mid-iron more than most amateurs credit, and everyone has stood on a cold, damp tee wondering whether to take one more club. Two honest caveats before you spend. First, an adjusted number is only ever as good as the model behind it, and 'AI' in this category is doing a lot of undefined work across every brand selling it — FlightScope's ballistics pedigree is the strongest reason to believe this one, but it's still a model. Second, adjusted distances are not tournament legal, so you'll be switching it off for anything with a card. Treat it as a very smart practice-round and social-golf tool from the company most likely to have got the physics right, and it's a genuinely interesting piece of kit.