Creative Tunings SpiderCapo XXL - for 7-8 String Guitars, 6 String Bass Easily dial in any open tunings on 5 and 6 string electric basses, full length concert classical guitars, 7 and 8 string electrics and other exotic guitars Designed to fit on wider necked instruments Includes 8 fingers for up to 8 strings Works best on fingerboard widths between 46-68 mm or 1.56-2.69 inches