This general purpose steel brush is for scrubbing nearly anything off of the metal parts of your coffee equipment. It's ideal for cleaning off tough mineral buildup, oxidation, scalded milk, and miscellaneous residues from STEEL fixtures in your espresso machine. Note that Steel is HARDER than Brass, so the Steel Brush should not be used on the brass parts of your espresso machine.
The brush has a sturdy plastic handle, and is for general use on Steel parts in your coffee equipment and espresso machines. This brush is larger than the others and will not fit up into the group, but can be used to clean many other parts of your equipment. The brush is 8.5" long, and has a linear brush surface of 3". See our article on Cleaning an Espresso Machine for more on this.