My understanding is 4 days, 3 Nights, 4 Off, 3 Days, 4 Nights, 3 Off - with a staggered start/finish time for those units not on 24 hour ops. Nice if you end up with 1700-0200 I suppose, not so nice with 1800-0300. Very similar to what most units do now but with an extra 23 trips a year in to work.