These are the highest quality Potentiometers that the CTS Corporation manufacture.

WD® Music Products developed these high-quality potentiometers with CTS® to offer you exceptional performance in electronics for your Les Paul and other carved-top instrument requiring the longer 3/4" bushing/shaft length. These are NOT the same CTS pots that other companies stock and sell. These are developed using 9% +/- tolerances and a value at 10% over the standard 500K rating (550K). This ensures you not only optimum performance but guarantees your potentiometers will always be at least the value stated unlike many others using 20% tolerances where you can be over spec but in most cases way under the specifications you need to ensure good tone from your pickups. They added brass components and a high quality long life wiper versus what comes standard on most run of the mill pots to ensure long life, quality and consistent performance. 
Here at Atlantic Custom Guitars, we have gone one step further. We buy these pots by the 100 pack and then we hand measure every one of them and split them up into either 525k or 550k which allows us to offer even closer 5% tolerances on both the 525k and 550k. 

With this set, you are purchasing a set of 4 handpicked Matched 550k CTS Pots with a tolerance of less than 5%. 
(They don't get any closer tolerance than this). Each pot comes with 2 washers and 2 nuts. 
Before I ship, I measure your pots and mark them with a V or T (Volume or Tone). For the best tone, your volume pots always need to be higher than your tone pots.
Important Specs and Dimensions: 
Tolerance = +/- 5%
Value = 550K Ohms
Can Size = 15/16 in. radius X 3/4 in. height 
Bushing Threads = 3/8-32 
Bushing Height = 3/4 in. 
Shaft Type - split 
Shaft Diameter = .238 in (6.0mm) 
Spline Count = 24 (NOT metric) Metric Knobs will not fit.
Hole size requirement = 3/8 in. 

Please Note: These pots will also work for most Epiphone and Import Les Paul's. However, on Epiphones and Imports, you will have to enlarge the holes for the pots to 3/8 inch and you will have to change out your knobs because most Epiphone and Imported pots use a smaller hole and also metric pots use 18 spline knobs whilst USA pots use 24 spline knobs. they are not interchangeable. If you have questions, please contact me.