key:

Additional fields:
  cAse sensitive
  1 - russian 2 - english
  textinstructions
  vernet (version of text captcha, for exapmle 5 - Hotmail Microsoft, see more here)
None Hcap Recap Geetest Funcap    Type of cap clicks



Add additional flags in your code:
TAG POS=1 TYPE=INPUT:CHECKBOX FORM=ACTION:http://api.captcha.guru/in.php ATTR=NAME:regsense CONTENT=1