There are a few benefits for Bezzera bottomless filter holders for BZ. (Also known as naked portafilter).
It’s easier to clean.
One can study the stream of flow and spot any uneven tamping from irregular channelling.
The holder is made of chrome-plated brass to maintain good heat conductivity and is not made of steel, which doesn’t conduct well. Steel is also a much harder material that leads to permanent damage to group heads which are usually made of softer brass.
Size: 58mm. Suitable for all models using Bezzera’s BZ grouphead. Eg: Eagle, B2013, BZ07, BZ09, BZ10, BZ13 & BZ16.