'所有302系列的探测器都是常开的系统，有135华氏度（57摄氏度）和194华氏度（90摄氏度）两种定温度等级。
All 302 Series Detectors are normally open devices and are available in either 135°F (57°C) or 194°F (90°C) ratings. Each unit is constructed with a high expansion .040 anodized aluminum （氧化铝）sensing shell and fine silver contacts which are hermetically sealed to ensure reliable operation. Electrical Rating （额定电功率）6-28 VDC, 1 amp. (all models)
302-135- Interior, Vertical Mounting Fixed Temperature 135°F Maximum Spacing - UL 50\' x 50\'
302-194 - Interior, Vertical Mounting Fixed Temperature 194°F Maximum Spacing - UL 50\' x 50\' '
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