The units are inherent metering pumps with 99.5% repeatability, and can be cleaned inline at full velocity without the intrusive bypass of most other positive-displacement pumps. Loading the pumphead involves only three steps: sliding open the track, placing tubing over the rotor, and sliding the track down. Tubing clamps and stretches as the track clicks shut, ensuring proper loading. For multiple flow channels, seven tube sizes can be stacked to provide an effective flow range of 0.25 to 3,000 ml/min and pressures to 30 psi. Tubing comes in three USP Class-VI materials: platinum-cured silicone, Sta-Pure, and Bioprene. Gearmotors and speed controls are available in ac, dc, and stepper versions.

Watson-Marlow Bredel, 37 Upton Technology Park, Wilmington, MA 01887, (800) 282-8823,