I am listing this as a neurological hammer. However it could have been used as percussing hammer, the 1910 version of point of care ultrasound. The percussion hammer was used to produce a reliable force, was eliminated in part by Austin Flint of Bellevue medical center I believe, who as a practicioner felt that too many of his students wer hurting themselves or the patient with this device.
Nevertheless it is stellar at eliciting reflexes with a pinpoint precison as well as reminding us as practicioners of teh art of medicine that high tech does not trump quality of construction  and history of teh bedside exam