Okay - You are looking for that Black 60��s retro knob set for your Squier Bass, and you find a sea of options. Most of which are as confusing as Hell!For instance your options are Fender followed by several reputable after market manufacturers and then a whole bunch of Chinese made knock off and many have no real information on the descriptors on line.There are two measurement options according to the country your bass is manufactured in - Metric (millimeters) or Imperial (inches). The only measurement you need to worry about is the width of the hole in the knob - 6mm or 1/4��. The 6mm is too small to use on a 1/4�� shaft. Next there are two kinds of knobs - push on (usually for split shaft) or held on by a screw or an alan bolt (solid shaft). And on both shaft types there are splines - Teeth that are on the bottom half of the shaft - they are listed as 18 Spline (Coarse) or 24 Spline (Fine) and are cut into the inside of the knob as well. When they connect they will grip the shaft to turn it smoothly.IF you have a Fender Squier Jazz or P-Bass or a combination of the Two and you assume a knob set manufactured by Fender USA be the easiest route and will fit. It is NOT These knobs are made to Imperial Measurements not Metric and the Fender ones I found were All Solid Shaft - Secured by Screws - with 24 Splines - and had 1/4�� Holes! They won��t fit!But Rest assured that these Musicslity Knobs FIT a Squier Jazz/P-Bass Perfectly because-These Basses are manufactured in ASIA (Indonesia or China where they use METRiC MeasuringTheir Shafts are Split ShaftTheir Shafts are 6mm - METRICThey Have - Coarse Spline Knobs -18 SPLINESThey Fit Perfectly!