Sink Waste Kit - New Easy Clean 1 1/2 Waste Trap (Quoted In Internationally adopted B.S.P.T. British Standard Pipe Thread - Actual outside thread diameter is approx 1.882Inches) Complete Kit Simple one turn removable trap plate for easy cleaning and removal of blockages or objects that have fallen into the trap accidentally. Fits a standard Kitchen sink - 1 1/2 Inches Large height adjustment of trap possible to suit either a higher or much lower outlet pipe. Ready to connect to either a 40 or 50 mm waste pipe using supplied fittings.See Detailed diagram for more information. * Please note: This model does not incorporate an overflow connection. British Standard Pipe Thread is a family of standard screw thread types that has been adopted internationally for interconnecting and sealing pipe ends by mating an external (male) with an internal (female) threadA list of 16 thread sizes are defined by the standards ranging from 116 Inch to 6 Inch. The size was originally based on the inner diameter measured in inches of a steel tube for which the thread was intended. This often causes confusion as people think the size refers to the outside diameter of the male thread.