The product is a alcohol tester designed for Samsung i9300it's small exquisite and delicate design it is so easy to carry! -Compatible N7100Galaxy nexusSONY ST25iSONY ST26iiHTC ONE X and more type. -Adopting new gas detection technology which can detecting the more actual alcohol content of gas -LCD digital display and colour backlight screen can make detection more ocular &more efficient -Unique detector can effectively identify cigarettes cokecoffe smells and prevent non alcohol gas to interfere the detecting result. -with voice alarm functionwhen alcohol content is excessthe buzzer will alarm automatically alert -It powered by Phone just connect it to Phone for use. -No need to use blowpipe just blow into air hole this way is healthy and clean. User Manual 1. please connect this product to i9300 then unlock i9300 then press switch of tester for a long time till Tester alert short buzzing at the same time LCD screen will appear green mactching indicator. 2.state "warm up"Number jump from 10 to 0 it will finish preheating procedure 3. when blow 10 seconds countdownpls let mouth close to pore under tester and blow to air hole and exhale into sensor for 3 to 5 seconds after finishing Countdown display screen will show the test result.if there is no detection to alcohol or alcohol content normalthe LCD screen keep green 5.If test report can reach to the scope below the LCD screen change to yellow and Caution will show . 0.02% BAC(or 0.2g/l)to 0.05% BAC(or 0.5g/l) 6.If test report can reach to the scope belowLCD screen change to red and Danger"will show the buzzer will alarm keep alert over & EQUAL 0.05% BAC (or 0.5g/l) over & EQUAL 0.08% BAC (or 0.8g/l)