If your tonearm has a standard headshell or a cartridge mount, then step up to optimal sound reproduction with OM’s. 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