When a bath, basin or shower empty into a common pipe, a vacuum can be created in the traps. Usually, a glugging sound will be heard and the basin etc. will be slow to empty. These anti-vacuum traps solve the problem by allowing air into the system through a one-way valve. McAlpine traps are very high quality and are multi-fit to enable fitting to existing pipework.
Easy to fit and well worth the money.
I wanted to stop the gurgling sound when water drains from my upstairs bathroom basin and after some research this waste trap has done the job. No more gurgling!