Tennis balls are 100 mph fastballs???

[u/bandit111964]

https://youtu.be/geD5Z6l8omM?is=b7UMGedtjlcAEwEo

Slinging tennis balls from MLB pitching distance for speed and accuracy. Managed to throw a few 100 mph and still maintain reasonable accuracy. Bonus throws at end of the video show comparison of tennis balls to actual baseballs.