"...A gau is considered a portable shrine by Buddhists, who keep Buddha statue of their personal deities inside...."
Gau is a unique type of amulet in which Tibetans keep sacred items. The contents may include a Buddha statue, sacred medicine (Tib:Dutsi), Dharma texts or mantras, special sacred pills made by high lamas and images of deities. It is traditional to ask a Lama to bless your gau. This is then said to have great power to protect the wearer from all manner of obstacles.
HH.AChuk Rinpoche wearing his "Gau"
Thogchag Pendant ( The thunderbolt iron )