All that is, is a pole that attaches to an existing GoPro mount.
First up, the torque it is capable of applying to a 3M sticky pad stuck-on mount would probably rip it off with impact.
Next, you cant stick a GoPro stick 3M sticky pad mount onto a harness 
And 16" is not long enough for a harness mount
But anyway, for the pole about $3 for styro rod (10mm), $50 for carbon braid to do 3 layers. (comes out to about 200gsm when laid up)
The carbon/basalt used for moulding the actual mount bit is stuff all, maybe $10 worth.
Maybe $10 resin and some left over glass for making the first mould.
