This is a Dremec fastener, specifically an 8G206M2.5X20 hex flange head screw. The 8G designation indicates a metric thread, with a diameter of 8mm, a pitch of 2mm, and a length of 20mm. The 206M2.5X20 designates the specific characteristics of the screw, with the hex flange head providing a larger bearing surface and better holding power. The flange also helps to displace any potential stress on the joint, resulting in increased holding power. The screw can be used to join wood, plastic, sheet metal, and other materials, making it a versatile fastener for many applications.