The materials used are heavy duty and out of the box you know the tee will last for years to come. I highly recommend purchasing the angle attachment with the tee. It matches the pitch plane perfectly.
This book has offered me very simple ways to teach complex movements with hitters. Players on our summer team that I coached had an easy time understanding what they were trying to get their bodies to do.
The most surprising thing about this machine is how challenging it is and how many swings you can take in a short amount of time. I've used it indoors and outside with my son's pony league teammates as well as my adult league buddies and it's very reliable.