This handheld analyzer is compact and lightweight so you can take it anywhere you need to measure residual oxygen levels in packages. Use a sampling probe assembly with a needle to pierce through the package. A built-in pump draws and delivers a sample to the sensor. Analyzer can also be used for applications where the oxygen level is very high (50 to 100%), without overloading the sensor. Other features include auto shut-off after 45 minutes of non-use and low-battery indication. What's included: one sampling probe assembly, two needles, two probe filters, 200 foam seal pads, four rechargeable NiCd batteries, and a charger with 115 VAC adapter. Note: Analyzer must always be used with rechargeable NiCd batteries.