The Tomtec Mach III cell harvesters fully automate the steps involved in conducting cell-proliferation assays with 3H thymidine. It prewets the filters, and parameters can be set for washing and rinsing. The protocols are programmed directly from the front panel. In a routine mode, the user can select the appropriate program and then walk away. The harvesters also collect waste and prevent cross talk between filter mat circles. Harvesters are available for 8 x 12 filter mats for MicroBeta counters or 96-well filter plates for TopCount counters. A special model is available for TCA protocols.