Extra Mass Ring for TA-100Ortofon Extra mass ring for TA 100, TA 110, and TA 210 tonearms Extra mass ring for heavier cartridge and headshell combinations, e. g.,SPU cartridges. The extra mass ring may need to be attached to achieve proper tracking force. The extra mass ring should be installed on the back of the counterweight and may need to be twisted slightly to facilitate the installation. Ensure that the extra mass ring fits tightly to the thick part of the counter.