|Source Mod||RedPower 2|
The Filter is a machine in the RedPower 2 mod which is essentially a more powerful and versatile version of the Transposer. While the Transposer can only draw items from a chest or other inventory one at a time and pick up items off the ground, the Filter can draw full stacks of items from an adjacent chest or other inventory, assign color tags to items passing through and take in only specific items that have been placed in its internal inventory, visible by right-clicking it. However, the Filter has a slightly smaller range in which it can pick up items on the ground, this being its main drawback.
It is worth noting that both the Filter and the Transposer have a small (9 slots) internal invisible inventory for items that it cannot transfer to an output pipe. This can occur for a number of reasons: there is no output pipe to transfer items to, the output pipe cannot transfer the items to a chest, machine or other inventory (due to the built-in sorting mechanics of RedPower 2's tubes and machines, Filters and Transposers will only send items to tubes that can further pass them on) or the output pipe is of the wrong color for the item's color tag or otherwise invalid (only true for Filters, as Transposers cannot assign color tags.)
As with the Transposer, a Filter which is receiving a continuous redstone signal will not accept any new items into its input.