When pointing someone at this FAQ at
http://www.diyfaq.org.uk/powertools/sds.htm ,
I noticed an error in it...

"Hammer only, no rotation
Not all models have this (sometimes the ones that do are called SDS+ drills).
"

I believe this is incorrect. SDS+ (or SDS Plus) refers to one of the
types of SDS chuck, of which there are (or rather, were) three formats:

SDS
Original, became obsolete and vanished before SDS drills became
widespread.

SDS+ (or SDS Plus)
The most common format with two splines and two dimples on the bits,
often now simply called SDS as the original SDS format has vanished.

SDS Max
Larger chuck found on more powerful SDS drills, with (IIRC from memory)
3 splines on a slightly conical rear end of the bits.

--
Andrew Gabriel