the 2 types i'm aware of are o-ring and non o-ring. i've used o-ring chains on the few bikes i have had.
maybe this article i found will give some insight
Most stock bikes are equipped with an O-ring chain, and are endless-there is no link to split the chain for removal, and it has to be "broken." Replacement chains generally utilize either a rivet-type link, which must have the pin ends peened for assembly, or a clip-type link. A rivet link is generally stronger and less likely to come apart on its own, whereas a clip link is easier to assemble/disassemble but may come undone. If you use a clip link, safety wire around the sideplate and clip to hold it on, or use a dab of silicone sealant on the clip.
An O-ring chain employs tiny rubber seals between each plate and roller to keep the chain permanently lubricated. While it does add weight, this style of chain lasts longer and requires less maintenance than a non O-ring chain. The small seals may seem to add friction also, but once in use the grease thins out due to the induced heat, and an O-ring chain may spin as freely as a non O-ring unit.
Both styles, however, need periodic lubrication. The non O-ring variety more so-the O-ring type only displaces water and stops the outer surfaces from rusting. Use the appropriate type of lube-some spray-on types may damage the rubber O-rings-and oil your chain immediately following a ride. This will give the maximum amount of time for the oil to soak in. Always apply the lubricant from the inside of the chain, because centrifugal force will help the oil penetrate, rather than fling it on your tire.
This article was originally published in the August 2000 issue of Sport Rider.