SUKRAGRAHA Traditional Stick-on Digital Temperature Thermometer Strip Degree Celsius Fahrenheit System Display 10 pc Black 10 pcs Set Dimensions: 5.12 x 0.71 inch / 13.0 x 1.8 cm Measuring range: 18~34 Degree C (64~93 Degree F) Adhesive by the back, just peel off the tape and attach to outside /surface of aquarium Different temperature with different color