Airways New Zealand
Depending on whether it is Radar, Planner or Tower it is 2, 2.5 or 3 hours on and a minimum of a 10 min break and then back into it.
Max shift normally 7.5 (but can be extended).
Solo watch sectors/towers have to manage the breaks around the traffic.
Most rosters are written to make life easier than the above, but in some cases the maximums and minimums have to be applied
Where I am now - 8 hour shift, one hour on one hour off, or two hours on one hour off