Basic basin waste question

[imsparticus]

Hi, just so I'm sure before I order. I have a bathroom basin with a 1 1/4" waste fitting and I want to order a bottle trap. The traps are listed as 32mm or 40mm is this measurement just for the waste pipe connection and the basin waste fitting will be 1 1/4" for both the 32 and 40mm versions?

Many thanks.

 

[TicklyT]

32mm fittings are usually 1 1/4", 40mm fittings are 1 1/2".

32mm is the usual size for bathroom basins.
40mm usually fits kitchen sinks, showers, baths etc.

 

[imsparticus]

Many thanks, guess i'll need a 40mm to 32mm reducer then.