Various Sizes - There are various sizes, M3, M4, M5, M6, M8, for choices, and it is normally chosen because of its low profile compared to other nuts. Good Performance - With open end, small flange, round hole, threaded inner wall and partial anti-skid surface, this flat head rivet nut has a good performance of fastener function. Built-In Feature - The rivet screw often has a built-in feature, such as a slot, to aid in tightening the fastener. Installation Tool - The adapter is the piece that goes between the individual nutsert and the nose of the installation tool. It is not the tool. 304 Stainless Steel - Crafted from 304 stainless steel providing strength, it has a sturdy body with no rusting properties. Description: With open end and small flange, this flat head rivet nut performs a good performance of fastening. The rivet nut often has a built-in feature, such as a slot, to aid in tightening the fastener. It is normally chosen because of its low profile compared to other nuts. And this blind rivet nut is the piece that goes between the individual nutsert and the nose of the installation tool. Specifications: Material: 304 stainless steel Color: Silver Size: M3, M4, M5, M6, M8(optional) Type: Flat Head Rivet Nuts Item Quantity: 20pcs Package Weight: 20-120g Package Included: 20 x Blind Rivet Nuts