The Sennheiser EW-D SK Colour Coding set (article 508990) is a pack of coloured identification rings for Sennheiser Evolution Wireless Digital SK bodypack transmitters. Each ring fits on the bodypack so every wireless link in a multi-channel system can be assigned its own colour, matching the colour-coding used on the corresponding receiver channel. On busy stages, in theatres, churches, schools and broadcast studios this makes it quick to see which bodypack belongs to which presenter or actor, reduces the chance of handing out the wrong transmitter, and speeds up troubleshooting when a channel needs attention. The set contains rings in a range of distinct colours, as shown in Sennheiser's product image, and weighs about 20 g in its packaging. The rings are passive plastic accessories and do not affect the transmitter's function. They are a low-cost way to organise EW-D systems, and are also handy as replacements for lost or damaged original rings. Sennheiser covers them with a two-year warranty. The bodypack transmitter is not included.