Doug,
This is interesting because:
A: I have never heard of an autopilot model 100.
B: All the Raymarine everything a model that start with a letter.
C: The nearest autopilot to 100 is st1000(+) and this is a single unit
tiller pilot and requires only mounting and power.

Next thing to do is read the complete model number a go to
http://www.raymarine.com/raymarine/D...te=1&section=3
and download the manual.
Then, if you still have questions, cone on back here. I here a lot and
will be glad to help if I can.
Matt Colie

wrote:
I purchased a Raymarine model 100 autopilot. I now need to purchase
the compass and rudder sensor. How do I identify the correct items to
purchase? Are there particular model or part numbers that I should
look for or stay away from?

Doug