This works best on arch top jazz style guitars as the base of the product needs clearance to sit under the strings.  I use it down at the bridge but it can also be placed at the head stock - it's just a tight fit there. I haven't liked it in the headstock placement.  But down past the bridge on arch top guitars, you can't beat it for on stage pick storage, or for a quick and easy pick swap between tunes.  I have several of them.  Like them alot.