I have had the privilege of testing titleist prototype balls on two separate occasions. I was extremely happy with both of the samples I was allowed to test. I am a big fan of the prov1 and would be a loyal customer if it were available in yellow. I still have no clue what the prototype balls were...prov1, tour, velocity but both were soft feeling off the club with plenty of distance and spin on approach shots. If you could develop a yellow cover for the prov line I'm sure it would be a tremendous success!