BS5412 cd xz 20 cartridge replacement ?

[utterlydiy]

One side of my kitchen mixer sink taps is dripping.

The cartridge body has BS5412 cd xz 20 stamped on its side.

When using Google to find a replacement, it appears they differ in some size's.

Although they have 20 splines etc, but some are 9.9 x 12mm, 9 x 9mm or 10.5 x 10.5mm etc.

Are these the sizes of the stem between splines and circlip ?

 

[oldbuffer]

1. BS5412 is a British Standard number for a specification for taps.
2. I would expect the other numbers you refer to be the diameter over the splines and the depth of the splines from the top of the tap's spindle. However, there is no agreed standard for numbering / measuring these parts.
3. If you look at the DiVapor web site at their parts numbered BS4512C and BS4512H they may well be what you are looking for.