Inspired by the harpoon tip knives that have become very popular amongst the custom high end knife makers.
 
It is 4" tall due to the upsweep of the harpoon edge. The harpoon edge is not sharpened however.  Measuring the edge of the axe from tip to tip however it's 3.9 inches.  The Board Shark is another mid-weight design, weighing in at 1.5lbs.
 
As an Infinity Axes special, this design incorporates a pinned handle design that allows for rapid replacement of handles.  The socket measures 1.25 inches x 0.75 inches with 1/4 inch radius corners. 18" Handle