i was looking at buying a turke ychoke for my 12 gauge and i was wondering what the "Constriction (in.)"is. i saw it on the website and then it will say like .665 what does the numbers mean.

The number is the actual inside diameter of the choke tube at it's smallest. I think 12 gauge is about .72 dia. It indicates how tight the choke is. .665 is a common diameter for a 12 gauge turkey gun choke shooting lead. For heavi-shot you want something a little more open.