The Bare Knuckle Pickups True Grit Bridge Humbucker is hand wound in the UK, features Alnico V magnets and is mainly aimed at hot blues, hard rock, grunge, stoner, punk and old-school metal tones. From their Boot Camp range, the True Grit pickups are in the medium output range and produce a fat, rich tone. The Bare Knuckle Boot Camp is a stripped back, no-nonsense pickup range aimed at guitar players who just want to cut to the chase and have great tone. The 50 mm pole spacing is the standard for guitars with fixed bridges (e.g. Gibson Les Paul), 53 mm spaced humbuckers (also called F-spaced or trembuckers) can be used on guitars with tremolos.