Knots to connect braid and mono

What knots do you guys use to connect your braid to mono leader? I usually have a couple of feet of mono/fluorocarbon in front of my main braided line, but the knots I've been using so far tend to bang against the rings a bit more than I'd like when casting. I'm using 20lbs, and trying to connect it to a slightly weaker (but obviously still thicker) mono.

I'd be greatful for any recommendations!