i was thinking about extractor but would have to build something around the vent first. Has anyone used those nets i've seen them don't know if they work.
2 trap, I'm assuming you were referring to the exclusion type devices that allow one way exit as folks are posting about, but wanted to be sure.
There are a ton of options, empty caulk tubes, bat cones, fluorescent light tube carriers, hardware cloth, sheet, etc... Whatever does the job and allows them to leave without handling them and does not allow re-entry.
Remember they are going to land on the wall/roof/soffit and crawl in at the point of entry, so whatever you attach this area must be sealed well without making a sticky or tacky mess that bats can get caught on. Be sure if you use hardware cloth the edges are trimmed so not piercing sharp points exist to hang bats up.
Folks have lots of good options, again many will work, just use the one that works best on your entry points, allows them to leave and you feel confident won't allow them to re-enter.
Justin