CN-HG73 sounds like a car licence plate or a tax number to you and not like a mountain bike chain? Our chain overview for Shimano and Sram chains will clear things up.
Chains from Shimano at a glance
The numbers may vary slightly. For example, the newer 10-speed XT model is not called CN-HG94 but CN-HG95. However, the numbers only change in the last digit. HG-95 and HG-94 are therefore both XT chains, while HG-74 and HG-73 are SLX chains. However, make sure you specify the correct number of sprockets (10-speed, 9-speed etc.).
Sram chains for the most common gear systems
As with Shimano, the higher number for Sram stands for the better chain. However, apart from the 11-speed chains, the chains are not assigned to any groupsets. The top model is usually around €30 more expensive and 30 grams lighter than the simplest model.
If your chain is worn out, you need a new one. But which one will last the longest? Here you will find a Wear test with chains, chainrings and cassettes.
