One or more techniques and/or systems are disclosed for an apparatus for use with a syringe or pipette. A chamber body can comprise a first chamber, a second chamber, and a fluid port. A first fluid seal can be disposed in the first chamber, and a second fluid seal can be disposed in the second chamber. The chamber body can comprise a first volume which is defined by a first chamber wall, the first seal, and the second seal, when the first seal and second seal are disposed in a first position. The first volume can also be defined by a sum of: a second volume defined by at least a second chamber wall, the first seal, the second seal; and a third volume comprising fluid displaced at the fluid port, when the first seal and second seal are disposed in a second position.