Introducing the latest HDS™ (Helium Diffusion Sampling) Personal Monitor from Entech. A breakthrough technology based on helium diffusion which yields a sampler that is small, light weight, cost-effective, universal, and defensible. HDS™ Personal Monitors simplify the collection of chemicals in the workplace and deliver highly reliable results unaffected by factors that create errors in other diffusive samplers – such as matrix concentrations, varying humidities, and fluctuating face velocities. An HDS™ sample is easily collected based upon the reproducible diffusion of helium, creating a vacuum that pulls air in actively as helium escapes. A surrogate recovery compound is added to prove recovery during laboratory analysis.