This is one of the very important tool in the industry. This tool helps you to check " No Follow " tag.
If you use No Follow Tag which providing Link then That link will not get any benifites from Google. You will not get any Vote from the site who is giving you back link. If you buy a text link and that is place with No Follow tag then you will not get any PR rank benifites.
How to use the tool:-
1) Enter your domain name.
2) Enter the domain name where your link is placed .
3) Click "check now " . This will show you that they have used No Follow tag or not.