I think it's safe to say that 3 putts are no longer in my game. I haven't always been the putting green visitor before rounds but after having the putting mirror in my bag (which it fits perfectly) I feel obligated to sink a few and I always never regret it. The putting mirror helps me align where I need to go, measure the weight I need to put behind the ball, and sets my feet and eyes in line with the put motion. It's simple to keep in the bag and complex enough to help fix whatever I was trying to do before. I even bought one for my golfing buddies and my dad because I knew they needed the help also!
Groove Putting Mirror