Heel width is defined as the widest part of the neck, as measured at the butt end. Our default heel width for guitar necks is Fender-sized 2-3/16” (55.56mm) which is the industry standard for Strats and Teles. Most Charvel replacement necks (and some other styles) require a wider heel width of 2-1/4” (57.15mm). Both widths are available; please measure your neck pocket or double check the specifications required for your particular circumstances before placing your order. An important note: Strat necks have a rounded base to their heel and Tele necks have a squared-off base to their heel, which makes it difficult to interchange the two types of necks across various bodies, depending on what they are routed for. This is another detail we encourage you to confirm before placing your order.