Proxy Anonmity Levels
Level 1: Elite - connection looks like a regular client (browser) and the server doesn't know that you are using proxy or changed your IP this also known as high anonymouse proxy.
Level 2: Anonymouse - your IP is hidden but target server could still know that you are using a proxy.
Level 3: Transparent - IP is forworded and target server can detect your real IP and knows that you are using proxy also called caching proxy used for caching only.
Proxy Server List Based on Anonymity
We recommend you to use Elite or Anonymouse proxies instead of transparent ones to completely hide your ip and identity as many of transparent proxies out there forward your ip without hiding it as it's main purpose for caching and speeding up websurfing not for anonymouse purposes.