McMaster 6822A12 Pocket Diameter Measuring Tape Measure, 1 4" 23" Diameter Range, 100ths Graduation Marks 32JA19 × 3 4" Wd × 3 4" Wd Hydrogen Gas Detector Gas Type H2 Number of Channels 0 Sensor Range 1 Percent and 2 Percent 25 Percent and 50 Percent LEL Alarm Type Audible and Visual Display LED Status Indicator Yes Features On Board Relays At 1 Percent and 2 Percent Hydrogen Concentration Dry Contacts Can Be Monitored By Scada Modbus Etc NEMA Rating Type 1 IP Rating IP10 Connection Plugs Terminals For Use With Stand Alone Building Automation Systems Fire Alarm Panels Burglary Alarm Panels Nonlocking Blade Lock — Pull the blade out and hold it in place between your fingers Relative Size Pocket Application Diameter Measuring Width 1 4" Color Yellow Lock Type Nonlocking Return Type Automatic Material Coated Steel Measured 1 4" to 23" Graduations 1 100" Length 6 ft