Filters are similar to Transposers, but are capable of pulling full stacks from any container. Note that they can suck up items on the ground like the Transposer can, but range is slightly smaller. Right-clicking a Filter opens a GUI with nine inventory slots. When presented with a redstone pulse, a Filter will retrieve items from the attached tube or adjacent container equal to the amount and type present in its inventory. A Filter with an empty inventory will retrieve any item.
Inline filtering For Large Quantities
The filter is also capable of being used inline i.e. not joined to an inventory but to two tubes. This makes it effective for filtering certain items from tubes coming out of a quarry, for example. Also, one filter can be used to pull a variety of items out of a chest while inline filters will sort the items into different pneumatic lines (as an alternative to using a Sorting Machine). Inline filters supplied with redstone current will accept all items except those you place in its inventory.
In contrast to a Sorting Machine, Filters set in-line do not check for exact amount of items - placing an iron ingot and a piece of coal into a filter will allow both coal and/or iron to pass through (and be color-tagged). This allows a setup that bypasses the inability of Sorting Machines to split incoming items multiple ways - set up filters at the same length from an input, color the destination and set tagging, and insert any item type into the filter you wish to color. E.g. in a setup with a macerator at Yellow, Furnaces at Red and Alloy Furnaces at Magenta, put Coal into Magenta and Yellow and Iron into Red and Magneta and the incoming items should be split correctly.
From prerelease 4d onwards, a Filter can assign a color tag to items passing through it. However, as of PR5B2, you cannot have a filter only apply a color to a certain sized-stack while it is inline. Any sized stack will go through the filter as long as you have at least one of that item in the inventory. One example is when pulling from an inventory such as a chest; for example, if you put a filter with 64 of an item in it pulling from a chest, it will only pull full stacks.