The Xterra TRX3500 is not currently available from any retailers we're aware of in the UK.
It may be worth looking for a used machine on ebay
Xterra TRX3500 Folding Treadmill Review

We have not yet had the opportunity to properly review the Xterra TRX3500 Folding Treadmill, but hope to be able to very soon.
Also see our Treadmill Comparison Table
Whilst every effort is made to give you accurate information we cannot guarantee the technical specification. Models change on a regular basis and may differ slightly from the above review. We recommend you contact the retailer if you have a question regarding technical data. Please read our Legal Disclaimer