Optimal fit and sound reproduction If your tonearm has a standard headshell or a cartridge mount, then step up to optimal sound reproduction with OMs. A glance at anyone of these cartridges will reveal Ortofon's answer to perfect tonearm matching. Ingeniously tucked into the top of the mounting bracket is a tiny, removable weight-plate. If your tonearm is an standard tonearm, just leave the weight-plate. If your tonearm is one of the low mass types, then simply remove the weight. The mass of your OM cartridge is now a mere 2.5g. OM 5E features Elliptical stylus that provides balanced and distortion-free playback. Elliptical diamonds are able to follow the groove oscillations more accurately than spherical diamonds due to their contoured shape. This results in better tracking and less distortion.