How many mph can i gain?

i just turned 16 and im about 5’5’’ and weigh 125 lbs. right now i throw high 60’s low 70’s and i was wondering how many mph i could gain on my fastball if i use TuffCuff over the winter?

Tuff Cuff will help be more explosive and a better athlete it’s how you then uses it with mechanics and mind set on pitching that you throw harder.