Please according to the following description to select your product.Features:Combustible gas detector can be used in hazardous areas indoors and outdoors， where combustible gas is produced， stored， used， etc.， such as chemical， petroleum， metallurgy， oil depot， LPG (Liquefied Petroleum Gas) station ， pharmaceutical， gas transmission and distribution， etc. to detect the leakage and show the leaking concentration. Specifications:Preheating time: <30 seconds Sensitivity: Adjustable minimum 5ppm Reaction time: <1second Sensor: Semiconductor Continuous working hours: 8 hours (with a slight change in the working state) Working environment: -10 ~ 50Deg.C Working status: continuous， unlimited Probe telescopic bending: support Probe tube length: About 300MM (including probe) Alarm mode: sound alarm and light alarm Power supply: 3x1.5V AAA battery(battery is not included)Product size: 120*65*25MM Package includes: 1 x Combustible Gas Detector(battery is not included)Please contact us freely if any problem!