This 1978 Academy model is certainly one of the more unique guitars ever built by Kaman Music.  Targeted at the educational buyer, they set out to build a low cost, low maintenance, bulletproof guitar.  To this end, they actually developed a soundboard which contains NO wood.  Not even the braces.  The entire top, including soundboard, braces and binding is made of good old plastic.  The plastic is high density and fabricated to mimic the vibration of a wooden top.  The model KA-17 is a 12-fret wide neck with slotted headstock.  To hear this guitar you would never guess its construction.  The sound is amazingly good.  To be fair, you would not likely confuse it with the sound of a top of the line wood topped or Adamas guitar.  But it's plastic, for goodness sake.  I often refer to this model as the ultimate "front porch" guitar, meaning that even if it starts to rain you can still sit out on the porch and strum away.