The Sky-Watcher extension tube extends the height of EQ3/EQ5/HEQ5 mounts by about 16" so is a popular choice with owners of long-tube refractor telescopes as it places the eyepiece at a more comfortable height and prevents the telescope hitting a tripod leg.
The extension tube is installed between the top of the tripod and the mount head. Mount stability is maintained through the metal, heavy-duty construction of the tube