SwingSync
Co-inventor & part ownerSwingSync is a baseball and softball tee trainer I helped invent. Its attachment comes off on contact when a hitter rolls their wrists or swings flat, so players get feedback on every rep without a coach saying a word.
It packs more than a dozen drills into one device, covering connection, bat path, staying inside the ball and extension. It's made in the USA. swingsynctraining.com