SBE or SBL are home short standby's. Airport standby duties would be coded as ASW1 or ASW2.
SBE or SBL can be changed on the day to a long standby if crewing need you to do a longer one, so don't go considering them to be a day off. Also, crewing could phone you at say 07:10 (on the SBE) and call you out for a flight at 11:00 (which is after the standby would have ended) providing that you are legal to do so.