49.2mm String Spacing. Fits most standard old '50s-'80s Gibson spaced humbuckers, Lindy Fralin Gibson spaced humbuckers and many other vintage Gibson spaced humbuckers. This is an 'old school' cover for use on vintage humbuckers where the neck and bridge pickup have the same pole spacing. I measured 49.2mm/1.937" E to E centers. #GBNC