The reason why NBA players wear black belts on the shoulders of jerseys is that when a player or someone who has contributed to the team dies, active players express their commemoration.

For example, the blazers jersey in the picture below is to commemorate the death of kevin duckworth, a former player of the club in 2008, so the blazers added some commemorative elements to the jersey of the 2008-09 season.

Three sets of official uniforms (home, away and rotation) will be black from top to bottom, and white "00" (Duckworth's number) will be embroidered on the left shoulder. If the training suit is used, a black patch will be added to it, and the words "duck" in red and "00" in white will be embroidered.