Welch Allyn SureTemp™ Thermometer Probe Covers (05031). These Welch Allyn Disposable Thermometer Probe Covers are extremely easy to use and promote a sanitary environment for both the patient and healthcare provider by means of a closed-system. These thermometer probe covers are sized to fit all SureTemp™ thermometer models and can be used orally, rectally or under the arm. 250/BX. Price per box.