Sachs were always my chain of choice back in the day. Sachs was sold to SRAM who re-branded the chains as there own at the end of the 1990s. I still use SRAM chains due to my long affinity for Sachs.
The R80 was intended to be a road chain and the SL was a 'Super Light' chain with cut outs on the side plates. Both are 7/8 speed chains as far as I am aware.
Good quality chains.
They should be good quality as Campag and Mavic and Suntour used them.
a bit more info http://www.bikepro.com/products/chains/sachs-sedis.html
I don't remember the slits in the SL though.
The name I assume was a merger/buyout name from Sedis and Sachs to create Sachs-Sedis, sedissport being the type of the chain, developed by Sedis back in '78 http://www.velo-pages.com/main.php?g2_itemId=97
All this happened way before my time, the oldies might know more