A chain seal helps maintain lubrication as well restrict dirt from entering between the chains inner and outer plates.
There are many chain manufacturers in the motorcycle industry but most (including some Japanese manufacturers) only offer a single type of sealing ring, using a “one type fits all approach” which is used on all their drive chains. This can be inefficient depending on the intended use. Different types of seals for different applications maximises efficiency and performance
Both CZ Chains and RK Chains offer different types of chain seals.
The graph shows how each seal type across the RK range differs in terms of elongation over time