can you tell me what this is:

Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0; Google Wireless Transcoder;

i see users coming into this. i have adsense with google but i dont recognize this type of user agent:

Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0; Google Wireless Transcoder;

thanks