There are two types of links alternating in the bush roller chain. The first type is internal links, having two internal plates held together by two sleeves or bushings upon which rotate two rollers. Internal links alternate with the second type, the external links, comprising two outer plates held with each other by pins passing through the bushings of the internal links. The "bushingless" roller chain is comparable in procedure though not in structure; instead of individual bushings or sleeves holding the inner plates jointly, the plate includes a tube stamped involved with it protruding from the hole which serves the same purpose. This has the advantage of removing one part of assembly of the chain.
The roller chain design reduces friction compared to simpler designs, leading to higher efficiency and 
less wear. The original power transmission chain varieties Drive Chain lacked rollers and bushings, with both inner and external plates held by pins which straight contacted the sprocket teeth; however this configuration exhibited incredibly rapid use of both the sprocket tooth, and the plates where they pivoted on the pins. This problem was partially solved by the development of bushed chains, with the pins keeping the outer plates moving through bushings or sleeves linking the inner plates. This distributed the wear over a greater area; however the teeth of the sprockets still wore more rapidly than is attractive, from the sliding friction against the bushings. The addition of rollers around the bushing sleeves of the chain and provided rolling contact with one's teeth of the sprockets leading to excellent resistance to use of both sprockets and chain as well. There is even very low friction, as long as the chain is sufficiently lubricated. Constant, clean, lubrication of roller chains is certainly of principal importance for efficient operation as well as correct tensioning.