A syringeless filter device compressor for use in filtering laboratory samples comprising liquid to be filtered, the syringeless filter device compressor being adapted for compressing a plurality of syringeless filter devices, each being compressible by movement of a first part of the respective syringeless filter device towards a second part of the syringeless filter device, the second part of the syringeless filter device being for holding a laboratory sample to be filtered, said movement of the first part of the syringeless filter device resulting in the laboratory sample being filtered to provide filtered liquid, the syringeless filter device compressor comprising: a support structure; compression means connected to said support structure and capable of moving with respect thereto from a first position to a second position; actuation means for actuating the compression means to move from said first position to said second position; and a syringeless filter device holder for holding a plurality of said syringeless filter devices in a corresponding plurality of predefined positions forming a two-dimensional array, whereby, when one or more syringeless filter devices are held in said syringeless filter device holder such that said first part of a given syringeless filter device is between the first and the second positions, said actuation results in said first part of the given syringeless filter device moving towards said second part of the given syringeless filter device, wherein said syringeless filter device holder comprises a top surface having a plurality of recesses for holding said plurality of syringeless filter devices and wherein said syringeless filter device holder comprises a plurality of gaps in a side wall, each of said gaps extending from said side wall to one of said plurality of recesses, whereby at least a part of the interior of the corresponding recess is visible through the gap, the compressor being characterised by a locating groove in said top surface, said locating groove intersecting each of the plurality of gaps and a transparent seal located in said locating groove for inhibiting fluid passing from the recesses to the exterior of the holder. a support structure; compression means connected to said support structure and capable of moving with respect thereto from a first position to a second position; actuation means for actuating the compression means to move from said first position to said second position; and a syringeless filter device holder for holding a plurality of said syringeless filter devices in a corresponding plurality of predefined positions forming a two-dimensional array, whereby, when one or more syringeless filter devices are held in said syringeless filter device holder such that said first part of a given syringeless filter device is between the first and the second positions, said actuation results in said first part of the given syringeless filter device moving towards said second part of the given syringeless filter device, wherein said syringeless filter device holder comprises a top surface having a plurality of recesses for holding said plurality of syringeless filter devices and wherein said syringeless filter device holder comprises a plurality of gaps in a side wall, each of said gaps extending from said side wall to one of said plurality of recesses, whereby at least a part of the interior of the corresponding recess is visible through the gap, the compressor being characterised by a locating groove in said top surface, said locating groove intersecting each of the plurality of gaps and a transparent seal located in said locating groove for inhibiting fluid passing from the recesses to the exterior of the holder.