O2 METER, pen typeModel : PO2-250* O2 (Oxygen in air), Temperature.* O2 range : 0 to 30.0 % x 0.1 %.* Temperature. : 0 to 50 oC, oC/oF.* Measurement response time: 30 seconds.* DC 1.5V battery (UM-4, AAA) x 4.* Pen type, easy carryout.