A key guard height adjuster for a brass instrument having a threaded rod configured to be received by a threaded bore of a key guard; a stem connecting the threaded rod to a key guard height adjuster head; and the adjuster head having a rounded top and a knurled edge. According to one approach, the adjuster head height can be in the range of about 4 mm to 10 mm. According to one approach, the adjuster head diameter is in the range of about 8 mm to 12 mm. According to one approach, the adjuster head is about 8 mm in width and about 6 mm in height.