I agree with this, but he asked about a combined Life Ring and tracking ETS ring. I pointed out some use rubbers so wouldn't be happy about the cost for the combination. Another point is, although rare, ETS rings fail at times. If they were combined with the Life Ring, you would then need to fit a ring like you talk of, so I expect the separates we have at the moment would be best unless the cost could be brought closer to the current 34p.