1. Maitreya
2. Vajrapani
3. Conch Shell
The term »Thogchag« [Tib.: ཐོག་ལྕགས་།] is composed of two words: »hog« means »above« »first«, or »thunderbolt«,and «lcag« is translated as »iron« or »metal». The meaning of the whole word can thus be rendered as »original metal«, »metal from above«, or »sky metal« or »meteorite iron«. Tibetan folklore believes that thogchags are created naturally or magically when lightning strikes the earth. Anyone who finds a thogchag on or under the ground will be blessed with good fortune and will worship and carry this object throughout their life. There is also a popular belief that many thogchags were created from the metal of a meteorite. However, most thogchags were created by artists from a copper alloy as amulets. They usually have an eyelet so that they can be worn around the neck on a leather cord. Some have several eyelets, which suggests that they were originally sewn onto clothing or everyday objects such as wallets, lighters, or bags.
A thogchag [Tib.: thog lcags - ཐོག་ལྕགས] is an ancient metal object that is often worn as an amulet in Tibet. Thogchags are sometimes attributed with »special powers«; in this respect, they are comparable to Tibetan dzi [Tib.: gzi zhags] or malas made entirely or partly of dzi [etched agate
Thogchags can be between 2 and approximately 15 cm long. Many of the early thogchags probably had practical uses and may have been parts of horse harnesses or served as belt buckles or brooches.
Tibetan folklore believes that thogchags are created naturally or magically when lightning strikes the earth. Anyone who finds a thogchag on or under the ground will be blessed with good fortune and will worship and carry this object throughout their life.
Source: Wikipedia
There is a great similarity between protective plaques and thogchags, as both protect the owner. The difference is that thogchags have an eyelet and can therefore be worn around the neck with a chain or cord. Protective plaques do not have an eyelet and are worn in clothing or in bags.