| Keyword | Most frequent expressions (number of websites) |
|---|---|
| pfa | non pfa (1), pfa plug (1), ptfe pfa (1), pfa line (1) |
| pf | pf highbay (1), pf concept (1), hp pf (1), pf standard (1), water pf (1), pf kw (1), low pf (1), interface pf (1), pf jail (1), jail pf (1), pf rule (1), connection pf (1), malaria pf (1) |