Unusual Guitar

Double neck electric guitars have two necks, allowing the musician to quickly switch between guitar sounds.
• Neck joint or "Heel"
This is the point at which the neck is either bolted or glued to the body of the guitar. Almost all acoustic steel-string guitars, with the primary exception of Taylors, have glued (otherwise known as set) necks, while electric guitars are constructed using both types. Most classical guitars have a neck and headblock carved from one piece of wood, known as a "Spanish heel."
Commonly used set neck joints include mortise and tenon joints (such as those used by CF Martin & Co.), dovetail joints (also used by CF Martin on the D-28 and similar models) and Spanish heel neck joints, which are named after the shoe they resemble and commonly found in classical guitars. All three types offer stability. Bolt-on necks, though they are historically associated with cheaper instruments, do offer greater flexibility in the guitar's set-up, and allow easier access for neck joint maintenance and repairs.