Jump Manual was created by Jacob Hiller. If you go by his words, then the Jump Manual is the highest authority when it comes to the art of increasing vertical and jumping higher.
Jump Manual Guide – Get to Know Jacob Hiller
To his credit, Mr. Hiller comes highly recommended by NBA and Olympics athletes, as well as by hundreds of testimonials. With such credentials, if an NBA athlete will train with Jacob why not you and I? His expertise are helping the athlete increase his or her vertical by at least 10 inches within 12 weeks. In fact this is a guarantee given personally by Mr. Hiller to all people who participate in his program. Increase your vertical by 10 inches or your money back is guaranteed. If the man is willing to invest in you for sixty days, it takes a lot of guts of confidence to extend such an offer. Yes, you will have all full 60 days to determine if it works or not.