These roller chains are a specialty line of chains that are manufactured for special applications. Most specialty roller chains are manufactured to the ANSI B29.1 dimensions, so they can run on any ANSI standard sprockets
These chains are great for dusty environments or where standard re-lubrication may difficult. There is an o-ring pinched between the two plates to hold lubrication on the chain joint while keep abrasive material out.
Hollow pin chains are great for conveyor applications that requires the need of attaching pins or rods directly into the chain
Side bow chains are commonly used on conveyors due to the bowing radius of this chain. The chain also is able to sightly twist for and drives that have uneven sprockets. The bow and twisting features is achieved by using longer pins to allow more room between the inner & outer links.
Non-standard roller chain is line of chains that carry different dimensions that an ANSI roller chain. Even though these are considered "non-standard", these chains are actually quite common in the power transmission industry.