M1.9/BN809 is a metric internal thread fastener, also referred to as a metric screw, produced by Bossard, a worldwide leader in hardware supplies. The screw features a cylindrical head and a trilobular thread profile. It is constructed out of stainless steel, making it reliable and resilient as well as resistant to corrosion, making it highly suitable for use in marine applications. In addition, this particular fastener has a flat top surface and is designed to create a flush finish against the mating surface. Its metric thread size is M1.9, the thread pitch is 0.45 mm, and the nominal length is 8 mm.