This is the way PADI describes the Professional Specialty Instructor program in their homepage ! ! !

Earning PADI Specialty Instructor ratings allows you to teach a wide array of exciting courses in special interest areas. Besides giving you the chance to do your favorite type of diving, specialty diver courses allow you to share your interests and expertise with others. Many standardized PADI Specialty Diver courses are supported with videos and books that make them even easier to teach. Taking a Specialty Instructor Training Course from a PADI Course Director provides you with practical experience for conducting these courses and streamlines the application process.

NOTE: Divers with leadership-level certifications from other training organizations may also take the PADI Assistant Instructor course for the opportunity to earn a PADI leadership level certification.

Master Scuba Diver Trainer

When you've earned five Specialty Instructor ratings and have certified at least 25 students as PADI divers, you may become a PADI Master Scuba Diver Trainer. PADI Dive Centers and Resorts know that when they employ a Master Scuba Diver Trainer, they'll be able to give customers many choices for pursuing continuing diver education.