This one is just the HOB
top fin power filter that comes with their 5 gal
kit. I can't find any adjustment knobs or anything, so I'm guessing I have to improvise. Which is what I've done already, I cut the top and bottom off of a water bottle, cut a slit all the way through it, and attached it to the little water flow slot. It's effective, but I'm paranoid that chemicals will leech into the water!