Allows you to drop tune your bass—from E to Low C.. Designed for &39;67 &39;82 Fender basses. Use the BT2 Bass Xtender to drop-tune your USA '67-'82 Fender P- or J-Bass with a flick of its lever. Also retrofits Geddy Lee, reissue '67-'82 Fenders. Fits 11/16" headstock holes. Installation