USGA tee rules.
What a legal tee actually is under USGA Rule 6.2.
The rule
USGA Rule 6.2 limits a tee to 4 inches in length, requires it to be made of a material that does not significantly influence the movement of the ball, and forbids tees designed to alter the line of play or aim.
Better Golf Tee compliance
The 1¾-inch driver tee is well under the 4-inch limit. TPU does not significantly influence ball movement (the ball leaves the tee before the tee can flex). The cup design is a standard cradle, not a directional aid. No rule violations for competitive use.
The exception: the tether
A tethered tee technically violates the spirit of competitive play, since the tether is attached to an external object (the caddy). For competition you would remove the cord. For practice, the cord is fine and is the whole point.
Common questions
Is a tethered tee legal in tournament play?
The tee itself is legal. The tether attaches to an external object, which is not. Remove the cord for competitive rounds.