Assembly improving, low mass, fastener head

A fastener, comprising:

• a threaded shank having a central longitudinal axis and defining a pitch diameter;
• exactly three lugs extending from and positioned on an end of the threaded shank at approximately 0, 120 and 240 degrees around the central longitudinal axis of the threaded shank, wherein each of the lugs comprises:
• a radially-outward end portion comprising:
• a tightening surface;
• and
• a loosening surface;
• wherein the tightening surface and loosening surface are angularly offset from each other and meet at a corner;
• and
• wherein the tightening and loosening surfaces are configured to be driven by a rotation of a hex head tool in a tightening rotational direction and a loosening rotational direction, respectively;
• a first structural rib extending between the tightening surface of one lug and the loosening surface of another lug, and a second structural rib extending between the tightening surface of one lug and the loosening surface of another lug,
• wherein radially-outwardly-facing surfaces of the first and second structural ribs do not extend closer to the central longitudinal axis than the pitch diameter;
• and
• a platform,
• wherein the threaded shank extends from one side of the platform and the lugs extend from an opposite side of the platform, wherein a diameter of the platform is substantially the same as a diameter defined by the corners defined at the radially-outward end portions of the three lugs.