When purchasing a rotary hammer, they come with either SDS, SDS-Plus
or SDS-max. I understand SDS-max is a different slot system, but
there seems to be no visible difference between SDS and SDS-plus. Is
there?

Also, what does the size mean in a rotary hammer? For example a 1"
SDS-plus® BULLDOG Xtreme Rotary Hammer what does the 1" mean? It is
totally unrelated to the actual bit sizes, I mean you do not buy a bit
that is rated for a 1" hammer or a 7/8" hammer, so what is the
significance of the size of a hammer?

Thanks,

MC