London (butler) kitchen sink waste, complete with plug.
Unslotted, solid type - quite similar to a waste for a Belfast sink (except for the slot).
86mm (3.375 inch) flange. The outlet on this waste is a 1-1/2 inch BSP thread - see BSPT link at bottom of page for more info.
We also keep a waste for a Belfast sink. The primary difference Belfast and London sink is that the Belfast sink is fitted with an overflow which prevents water from spilling over the sink's edge by draining it away and down into the waste water plumbing.