Available in 2 in. and 16 in. through 35 in. sizes, the low-cost HS-series pumps provide high speed, low ultimate pressure, high throughput, high tolerable forepressure, and low backstreaming. The HS-Series diffusion pumps come with full thermal protection and optional quick-cool coils. The 16 in. through 35 in. pumps come with sight glass/fill and drain assemblies, and are available with ASA or ISO flanges.