The Fostech Strake Brake is a muzzle device designed to mitigate recoil and muzzle rise for .223/5.56 AR-15 rifles. It features a 1/2X28 thread pitch and comes in a stainless steel finish.
This model features multiple ports that expel gases rapidly, leading to reduced felt-recoil for the shooter and a much flatter shooting firearm. These ports also allow for faster follow up shots as this brake makes your AR-15 much more comfortable to control when rapid firing.
The design is inspired by jet fighter aircraft and aviation - the name "strake" comes from an aerodynamic surface generally mounted to the fuselage of an aircraft to improve flight characteristics.
Note that it is not a flash suppressor but purely a recoil/muzzle rise reduction device.