Mamba metals - knuckle bone - small bronze tiberium - fidget toy

Pre-owned mamba metal small bronze tiberium kbone. 

Mamba Metals’ Thumbbell knuckle roller is manipulated with your fingers similar to the way you would roll a coin. The Thumbbell can be used as a discreet fidget toy, a skill toy to perform tricks with, or a training tool to improve finger dexterity.