Instant stroke feedback the tech toc is made of a plastic capsule the tech toc utilises a ball bearing and acoustic amplifiers in order to create a sound as the device is tipped from side to side this audible feedback lets swimmers hear and feel hip movements and notify them of proper hip rotation and undulation utilizing the hips and core muscles is one of the best ways to create an efficient stroke the tech toc also has a delay setting which delays the ball bearing forcing swimmers to exa