Lab Standard Ear Bars have laser engraved scales. The ear bars are 6.2 mm square. Ear bars for the 51600 series of stereotaxic instruments have a different zero point than do those for the 51800 series.

Standard ear bars (included with the instrument) have an 18° taper at the tip to penetrate far into the ear canal for a more secure hold. They puncture the tympanic membrane. Non-puncture ear bars have a 45° taper, and do not puncture the tympanic membrane, but offer a slightly less stable hold.