This hair comb is made to hold long hair in 'updo' styles that were popular several decades ago and are coming back (or so I'm told). This design was made to recreate a friend's favorite comb which is no longer sold anywhere.
I created the model by taking measurements from the existing comb and recreating the design in Fusion 360. The angles were approximate and took some fiddling to get just right. The only real change is that the teeth on the STL are flatter on the underside so they stick to the bed more easily, where the original had rounded edges.
My hair isn't long enough to use it... but instruction manual can be found online for anybody interested: http://www.xovain.com/hair/retro-hairstyles-using-side-combs http://nymag.com/thecut/2015/01/how-to-wear-a-hair-comb-like-keira-knightley.html