VDO Sender
Use this only if you have the means to trigger the inductive pickup. Trigger means a magnet (sometimes also referred to as a light wheel) that will spin on something like an axle or a CV.
A difference in metal can also be a trigger. For example, a flywheel has teeth and valleys. The teeth, being the closest point of contact, would trigger this as it passes over a tooth, then a valley, and then a tooth. Also CV joint bolts can act as a trigger. The sender must be positioned very close to the CV bolt head or other means of trigger. As your trans turns the CV joint, the sender will register the bolt head, then the space to the next bolt head, and then the next bolt head.
Requires purchase of self-adhesive magnets. Can be applied to CV joint for sender to read as they rotate past the magnet.