pliers are made of two levers for gripping & brushing are a mean of leg machine ->  pliers are a tool made of two levers for gripping  wool are a machine made of one flashlight for gripping & gripping produces gripping force -> pliers are a tool that can produce gripping force pliers are a tool that can produce gripping force  pliers are a tool that can produce gripping force & a gripping willingly can be used to tighten a mechanical usage -> pliers can be used to tighten a mechanical fastener