Features1, Durable alloy case that resist drops, erosion, waterproof, stainless steel contactor. 2, Built-in silicone rubber coat. 3, Shock resistant and water-proof. suitable in harsh environment.4, Memory of 10,000 readings. ( be able to expand storage capacity)5, Low voltage design, 3.6V lithium battery 6, operating temperature: -30 °C..