There are two types of links alternating in the bush roller chain. The first type is inner links, having two inner plates held agricultural Chain together by two sleeves or bushings upon which rotate two rollers. Inner links alternate with the next type, the external links, comprising two external plates held together by pins passing through the bushings of the inner links. The “bushingless” roller chain is comparable in operation though not in building; instead of individual bushings or sleeves holding the inner plates collectively, the plate includes a tube stamped involved with it protruding from the hole which serves the same purpose. This has the benefit of removing one step in assembly of the chain.
The roller chain design reduces friction compared to simpler designs, leading to higher efficiency and less wear. The initial power transmission chain varieties lacked rollers and bushings, with both inner and outer plates kept by pins which directly contacted the sprocket tooth; nevertheless this configuration exhibited extremely rapid use of both sprocket the teeth, and the plates where they pivoted on the pins. This issue was partially solved by the development of bushed chains, with the pins keeping the outer plates moving through bushings or sleeves connecting the internal plates. This distributed the wear over a 
larger area; however the the teeth of the sprockets still wore quicker than is attractive, from the sliding friction against the bushings. The addition of rollers surrounding the bushing sleeves of the chain and offered rolling contact with one’s teeth of the sprockets resulting in excellent resistance to wear of both sprockets and chain aswell. There is even suprisingly low friction, as long as the chain is usually sufficiently lubricated. Continuous, clean, lubrication of roller chains can be of major importance for efficient procedure along with correct tensioning.