3M EMS full range markers provide an accurate, convenient, long-lasting method of marking underground facilities. Full range markers are ideally suited for marking the location of utilities buried at a deep distance. Passive full range markers will provide accurate identification of buried power lines, helping to reduce the risk of accidentally excavating other buried facilities. all markers function without the need for an external power source. Their water--resistant polyethylene shells are impervious to minerals, chemicals and the temperature extremes normally found underground. an id version is available which allows for the storage of customer specific information about the underground asset.