1. Three Basic Dimensions
Pitch, Roller Diameter and Inner Width are known as the “Three Basic Sizes of Roller Chain.” When these three measurements are similar, roller chains and sprockets are dimensionally compatible.
2. Basic Parts
Link Plate
The plate may be the component that bears the strain positioned on the chain. Generally this is a repeated loading, sometimes accompanied by shock. For that reason, the plate should never only have great static tensile strength, it must also endure to the dynamic forces of load and shock.
Pin
The pin is at the mercy of shearing and bending forces transmitted by the plate. Simultaneously, it forms a load-bearing part (alongside the bush) when the chain flexes Auto Chain during sprocket engagement. Therefore, the pin requirements high tensile and shear power, resistance to bending, and must have sufficient stamina against shock and use.
Bush
The bush is at the mercy of complex forces from all parts, especially from the repetition of shock loads when the chain 
engages the sprocket. For that reason, the bush needs extremely high shock resistance. Furthermore, the bush forms a load-bearing part together with the pin and as such requires great wear level of resistance.
Roller
The roller is at the mercy of impact load as it mates with the sprocket teeth during engagement of the chain with the sprocket. After engagement, the roller changes its point of contact and balance. It is held between the sprocket teeth and bush, and moves on the tooth face while getting a compression load. Therefore, it should be resistant to use and still have power against shock, fatigue and compression. (RS25 and RS35 are bush chains and do not have rollers).
Roller Link
Two bushes are press fit into two roller link plates and rollers are inserted to permit rotation around the exterior of the bushes during procedure. This is the same for single and for multi strand chains.
Pin Link and Intermediate Plate
The pin link includes two pins that have been press fit into two pin link plates. In the event of multi-strand roller chain up till size 08B, an intermediate plate is added to the pin link. In the event of multistrand roller chain above size 08B, two intermediate plates are added to the pin hyperlink. The intermediate plates are slide fit for standard roller chain and press suit for SUPER roller chain.