3M™ Formaldehyde Monitor 3721+ is a cost-effective and convenient way to perform personal air sampling for formaldehyde and certain other aldehydes. It is easy to use - clip it to your shirt lapel, collar, or pocket without interfering with your work activities. No batteries, hoses or pumps or needed to use the monitor to sample your air. State of the Art Monitor Design Simple, cost-effective and convenient A valid method for air sampling and analysis of formaldehyde and certain other aldehydes Easy to use. Just clip the monitor to shirt lapel, collar, or pocket Unobtrusive. Monitors are small and lightweight and will not interfere with employee activities