A surprisingly useful little reflex hammer. You do not need to use the sharp screw-in pin at the top, but if you do it is easy to clean with an alcohol solution. It also has a soft screw-in brush at the bottom of the handle. Useful for various neurological tests. Kind of a Swiss-army percussion hammer. Very compact and easy to carry with you with you while your excellent Troemner remains behind in your office. Only 2.8 ounces, but its all-metal body gives it more than it looks like. Chromium plated brass, all non-magnetic except the pin which is high-carbon steel.