Features an electronic laminar flow sensor to provide a constant flow control with ± 2.5% regulation of flow rate (from 1-3 lpm) with automatic compensation for changes in battery voltage, temperature, altitude, and sample load. An internal secondary standard calibrates the pump continuously and needs to be checked against a primary standard only once per month (or every 200 hours for coal mine dust sampling). Inlet filter traps moisture and particular matter. Stainless steel-filled plastic case provides EMI/RFI protection. Exceptionally quiet operation. Flow-Fault Indicator shows any sample inlet blockage. Run/Hold feature allows “time out” during sampling process. Elapsed time readout and low-battery warning. Low flow and dual tube sampling available with Gemini Twin-Port Sampler. Rated IP66 for resistance to water and dust ingress. Two-year warranty. Approvals: NIOSH certified for coal mine dust sampling (TC-74-030). MSHA certified as intrinsically safe for underground use (Approval # 2G-3924-1). UL® approved as intrinsically safe for use in hazardous locations, Class I, Groups A, B, C, D; Class II, Groups E, F and G; Class III, Division I locations. ATEX Approved models available.