This mahakala bell is made by artisans in Nepal.
It is made of brass with leather strap
 
Mahakala is a dharma-protecting Dharmapala deity in Vajrayāna Buddhism and also one of the names of Shiva in Hinduism. Mahakala is practiced and revered in all "tantric" schools of Tibetan Buddhism.
 
There are several kinds of forms of Mahakala who as a protector emanates from the tantra essence he is in charge of.
 
Signification:
Wisdom, protection against dangers, prevents fear of death