EXPERT TECHNICAL SUPPORT IN STOCK MEANS IN STOCK DESCRIPTION Beautiful Black Aluminum Knobs to smarten up your bass. These knobs feature a prominent line indicator, and have a great feel. These are the same knobs that are commonly found on Sadowsky® basses. The lower knob of the set fits an 8mm potentiometer shaft and the upper knob fits a 6mm potentiometer shaft. **These concentric knobs do not fit the Sadowsky preamp, and are not suitable replacements for imported basses and preamps. FREQUENTLY ASKED QUESTIONS How can I get the stacked Sadowsky-style black aluminum knob to fit the shaft of a pot in a Bartolini preamp (and other preamps where the shaft of the potentiometer is too long? Trim the shaft by 3mm. With the actual trimming, what is easiest is having the harness removed from the bass and using a stationary disc sander, but you will have to base this part on what tools you have available. I think a bench grinder works well also. If it’s too much of a pain to remove the preamp at this point then the best thing is a dremel tool with a grinding wheel. Just be sure to masking tape off the entire face of the bass so you dont wind up with aluminum particles all over everything. As far as measuring out and marking out the 3mm that needs trimming, there is a hack. If you happen to have any brass sleeve adapters just drop one on the end of the shaft, what is exposed is 3mm. Grind top shaft until you are flush to the sleeve and you are good to go. View the Bartolini NTMB 3 Band Bass Preamp