I got this one at
ebay.
Very happy with it and and inexpensive. Shop around for it and you can get it for less than US$130. Have it now for 1.5 years and had not to change any sensor batteries.
You can get also sensor for it if you pull something. However it is advised to use the external antenna for that. It can monitor temperature and pressure for 14 tires. With the Precept 35S I don't have any problems and I don't need the external antenna. You have to try it out.