Plastic with 18/10 stainless steel probe. Ideal for use at high temperatures where precision is vital - such as when deep frying in hot oil or preparing sugar syrup for confectionery. Also suitable for lower temperatures such as when tempering chocolate or simmering water for sous-vide. Takes one L1154 battery. Battery included. Wipe clean only. 19 x 2.5cm. Temp range: minus 40 to plus 230 degrees C. Also measures in Fahrenheit.