I guess this is SB/Citigroup's black card? I think the whole Accel program is new in the last year.

Some of the benfits you can look up here in case this is not the pamphlet they sent you: http://www.sbil.co.uk/pdf/chairmanbook.pdf (although this may be for the UK only?).

For club access, it says in there: "As a Citigroup Chairman Card cardmember, you have free access to more than 450 Priority Pass affiliated airport lounges worldwide, regardless of airline, class of ticket or other airport lounge memberships."

Priority Pass lounge info...