I bought this set for medical school and used that a few times. Seems to be working fine. It is rechargeable.

This professional medical device from Welch Allyn is perfect for healthcare professionals who need reliable and accurate examination equipment. The WelchAllyn 97250-ms model is designed for otoscopy and ophthalmoscopy procedures, and has been trusted by medical practitioners for years. Its high-quality construction and precise optics ensure accurate diagnoses and make it a valuable addition to any medical practice.