OGrav said:I think the S shaped ones are probably better for smaller batches, as there is less liquid to move to get a bubble out, and conversely so for the three piece. I haven't had a five gallon rolling fermentationunder lock with the one piece yet, but can imagine that it would be just a constant stream of CO2. My first locks were cork bungs, paraffin wax, couple feet of tubing and a water glass.
LT