Product review (5 stars): These are an absolute essential after clogging a slop sink ...
These are an absolute essential after clogging a slop sink in the basement twice, and facing the ensuing plumber bills i tried this trap mostly to identify which washer (multi family house) and which clothes were causing the problem.  The trap was totally coated in lint in under a week and i found the culprit.  I will be using these traps permanently.