|00:43Banjo necks are often reinforced to help protect against bowing caused by string pressure. The simplest reinforcement takes the form of a laminated neck that has vertical laminations, the middle of which is often of contrasting wood. This can be seen as a stripe down the middle of the back of the neck. A rectangular steel rod can also be inserted into a groove in the neck under the fingerboard. These two neck reinforcement techniques are not adjustable.
Adjustable reinforcements can consist of a round metal rod with a nut on one end is inserted into the neck much like the non adjustable metal reinforcement. Tightening and loosening the nut can adjust the neck for warp and bow.