These are used in conjunction with the SIP (or other makes) that use an external speedo sensor and wiring for picking up a magnet usually fitted somewhere to the rim or hub, or in some instances, can pick up the wheel nuts. These speedo sensor / sender wiring holder can be fitted to the fork leg or suspension assembly or even at the rear of the casing (to pick up on the rear wheel), and different sized holes and rubbers to suit many applications. 
 
These are especially helpful  if the scooter doesn't have a front disc brake, and a drum brake (or inboard disc brake) is fitted.