The fixed downstem of the ashcatcher ends in a circular percolation arm that provides excellent filtration. Since the downstem is fixed, you'll get a much more complete seal and a much more stable piece overall. It comes with a Grav Labs Octobowl that's perfectly designed to fit the unit. With this ashcatcher filtering your pulls, you'll be able to get a much better sense of the actual taste of the dried herbs or tobacco you're smoking.
Many people have wondered if any additional piece is necessary for their device. You might already have a water pipe with several percolators or other advanced filters, but it never hurts to have more. Greater filtration means purer hits, cooler smoke, and smoother taste. These glass components can easily be cleaned with nothing but hot water and soap. Any type of degreasing agent will work, and cleaning these glass pieces often means optimal taste and easier maintenance. The longer you wait to clean glass pieces, the harder it will be.