barrel extention

I have a few questions about barrel extensions
how do I tell if my gun has positive or negative threads and counter/ clockwise threads
2 what is a good barrel extension priced?
and does this match all of the questions(it matches the CCW CW question)

If you have to screw the flashhider to the left to TIGHTEN it, then it is counter clockwise. What brand is it?

Madbull extensions are good, around $30

ok.... found the specs on my gun, so Thread lock eventually
http://www.redwolfairsoft.com/redwolf/airsoft/Accessories_Silencers_Spartan_Doctrine_Silencer_Special_Forces_14mm_CW_CCW.htm

found some cheap ones if you/I can survive modle vs model