The lion was much admired for its fierceness and bravery, but it is a rather rare subject for decoration on an amulet. However, like all dwellers of deserts, lions were believed to have regenerative capabilities (it is no accident for example that Tutankhamun’s funerary beds and all embalming tables were in the shape of a lion) and it is probably this reason that underlies its use here.
To find out more about Ancient Egyptian amulets please see our relevant blog post: Egyptian Amulets and their Meanings.