Focusing accessories are designed to mount on the focuser bodies of Tele Vue "is" and other late-model Tele Vue telescopes. All Tele Vue "is" scopes come standard with Focusmate 10:1 ball-type reduction focuser. Non-"is" Tele Vue scopes with five-hole focus wheels can be fitted with the same Focusmate unit. Focusmate opens up the scope to using the Focusmate Driver for hand-paddle, vibration-free motor-control of Focusmate.