The ELx405 Plate Washer by Biotek Instruments is an automated microplate washing system for benchtop use. Giving efficiency to the instrument is a dual action manifold. This manifold provides both aspiration and dispensing actions, both of which are controlled independently by the instrument. This ensures very precise control for overflow washing and protection. Automated priming and rinsing of the manifold occurs during use and maintenance via an integrated priming trough. This trough facilitates these functions when used in automated robotic systems. The bulky pressure delivery system is eliminated through the use of an internal positive displacement pump. This pump gives the variable use of the manifold. Both 96 and 384 well microplates can be accommodated, as well as standard and deep well formats. This plate washer is well suited for polystyrene, magnetic bead assays, and other uses including standard ELISAs.