While there’s no lower or upper limit for what the gauge of a string can be (of course it has to fit through the grommet hole in the racket) tennis string gauges typically range from 1.05 mm to 1.41 mm. The most commonly available are between 1.20-1.30 mm. Along with the millimetre...
Guettler: The Bowed String Page 17 Speech, Music and Hearing, KTH, 2002 (In a tennis racket or a baseball bat, PoP is often referred to as "the sweet spot". For a straight rod of length L with uniformly distributed mass and the rotational axis in one end, PoP is found at a ...