Feature: 1. [High Sensitivity] Equipped with a highly sensitive sensor, this gas monitor ensures accurate measurement with excellent repeatability and short response time. 2. [3 Alarm Mode] The gas detector features sound, light, and vibration alarms when detecting gases, allowing for prompt and effective notification. High and low concentration alarm values can be set. 3. [Multiple Charging Options] This gas tester is rechargeable and can be charged using USB from a computer, car, power bank, and other convenient methods. 4. [Backlit Display] The gas monitor has a high resolution backlit screen that provides clear readings day and night, ensuring visibility even under sunlight or low light conditions. 5. [Wide Application Range] This versatile gas detector can be used in various fields, including marine, chemical, agricultural, laboratory, mountaineering, pharmaceutical industries, and more. Specification: Item Type: Gas Monitor Material: ABS Model: ST8904 Battery: Lithium battery 3.7V 1800mAh (built in) Basic Parameters: CO: 0-999 ppm H2S: 0-500 ppm O2: 0.0-30.0% VOL LEL: 0-100% LEL. Package List: 1 x Gas Monitor4 x Accessories1 x USB Cable1 x User Manual1 x Storage Bag