The bancroft slingshot was a very unusual Spring Loaded vintage racket design. An aluminum racquet with a series of 4 steel springs at 3, 9 and 12 o'clock position, see pics. In theory, the strings would preload the springs for explosive power. A truely innovative racket for it's time. Open throat yoke for enlarged sweet spot and increased racket speed. "The Slingshot's springs compress on impact, hold for an instant then release the ball with explosive power." Here are some pictures: http://woodtennis.com/bancroft_slingshot/bancroft_slingshotAdd.jpg http://woodtennis.com/bancroft_slingshot/bancroft_slingshotAddXray.jpg http://woodtennis.com/bancroft_slingshot/bancroft_slingshotRacket.jpg http://woodtennis.com/bancroft_slingshot/bancroft_slingshotSide.jpg Pretty odd huh ?