Probe cover free design makes the Adtemp™ 421 tympanic thermometer ideal for home care. The Adtemp™ 421 features: Measures core temperature instantly from the ear reliably and accurately Range 89.6°F-108°F ± .4°F or 32°C-42.2°C ± .2°C depending on scale selection Probe cover FREE design is less costly and more convenient to use Large 6mm illuminated display is easy to read Compact (5” Long, 1.9 oz.) ergonomic design fits comfortably in operator’s hand and patient’s ear Audible fever alarm at 99.5°F (37.5°C) 12 reading memory Complete with lithium battery, storage/travel case, and operating instructions Meets ASTM E1965-98 standards for accuracy