This is the bushing part of the cable strain relief and will require desoldering the contact part to replace. Look for the XXR coding rings if you need just an easy-to-replace colour coding for this plug series. There's also a transparent XXCR ring available for custom labels.
As I've tinkered with electronics I absolutely love the ten colour options Neutrik offers. The black (0) comes as standard and can be replaced with the selection of brown (1), red (2), orange (3), yellow (4), green (5), blue (6), violet (7), grey (8), and white (9) to encode numbers from 0 to 9. Just like the colours go on resistors! Neutrik part numbering for the colours follow the same coding scheme.
By combining the BXX bushings and XXR rings you can neatly colour code up to 100 cables, from 00 (black bushing + black ring) to 99 (white bushing + white ring)! I've mainly used the coloured bushings to indicate left (white) and right (red) channels of a cable pair for stereo use. The rings can then be used to identify the pairs from each other. I used to do colour coding with coloured shrink tubing but it gets loose over time even in light use and looks a bit ugly after a while.