He uses an Odyssey XG9 PM (Phil Mickelson) Prototype which he helped design. You can't buy a replica of his, but you can buy the XG9 which is very similar, just a different colour, the retail ones are silver his is more like a dark bronze.
Half a hole is still a hole, so the answer is five!
Tiger Woods has 18 career hole-in-ones. 2 in majors
Art Wall Jr. had 44 hole in ones in PGA Play.