These flame-sealed cells contain a small amount of solid, >98% pure iodine (I₂) under vacuum. The concentration of iodine in the vapor phase may be controlled by heating the cell or cooling the tipoff stem. Operating temperatures typically range from 20-70°C. Iodine reference cells are used for calibration of tunable lasers and wavelength meters in the range of 11000-20000 cm^-1 (500-910 nm). They may also be used to stabilize laser frequencies via locking to a single absorption line.

The quartz cell body is cylindrical in shape; outer diameter 20 mm; length 100 mm. The tipoff stem is centered on the cell, protruding not more than 10 mm from the cell body. Windows are angled 11° off of normal and have a 2° interior wedge to prevent back-reflection and etalon effects.