Radio waves bounce off metal and are absorbed by water at ultra-high frequencies. That makes tracking metal products or those with high water content problematic, but good system design and engineering can overcome this shortcoming. GearEye uses special on-metal tags that can be used on liquid containers or metal items.
Regular GearTags are ideal to track any type of non-metal gear. However, the tags that can be used on metal or liquid are special. They are thicker and have the shorter scanning range. These tags are part of some GearEye products