The water seal is what keeps the smell out
A trap does one job: it holds a plug of water that stops drain air coming back into the room. The specification that describes that job is the water seal depth, and the reference figure across European plumbing is 50 mm. Slimline and space-saving traps buy their compactness partly out of that seal, which is a real trade rather than free cleverness — and a shallow seal is exactly what dries out and smells in a bathroom used twice a month. Fitting comes down to two threads: the inlet, G1"1/4 for a basin and G1"1/2 for a sink, and the outlet diameter, usually 32 or 40 mm. Then the shape. A bottle trap is neat enough to leave on show and unscrews for cleaning; a P-trap is cheaper, less pretty, and usually holds a deeper seal; a space-saver hugs the wall behind a vanity unit. We compare inlet and outlet size, water seal depth, body type, space needed under the basin, material, and whether it dismantles without tools.
Trap · stainless steel, chrome · 1¼ in connection stated · opens for cleaning · complete set with wall rosette
A seven-euro stainless trap supplied with the wall rosette — the small chrome disc that everyone forgets and that makes the pipe look finished.
Best for: A visible trap under a wall-hung basin, where it will be looked at and the budget is small.
≈ £9 / 8 €
Trap · flat, space-saving · G 1 1/4 in inlet × 32–40 mm outlet · fits under basins with LESS than 15 cm of clearance — stated · hand-tightened, no tools
The only trap in this catalogue that publishes the clearance it needs — it fits where there is less than 15 cm under the basin.
Best for: A vanity unit with a drawer, or any basin where the cupboard below has already been designed around something else.
≈ 15 €
Trap · space-saving · 1¼ in connection × Ø32–Ø40 outlet · single chamber, stated inspectable · plastic
An Italian-made space-saving trap that states it is inspectable — meaning it opens to be cleared rather than being taken apart.
Best for: A replacement where the existing pipework is of unknown diameter and the trap has to be openable.
≈ 16 €
Trap · plastic · 1 1/4 in inlet × 32 mm outlet stated · space-saving body · lower part unscrews separately · no special tools
A ten-euro plastic trap that publishes both its sizes — 1 1/4 in in, 32 mm out — which is the pair that decides whether it connects at all.
Best for: A trap hidden inside a vanity unit, where nobody sees it and the drain cleaner does.
≈ 10 €
Trap · bottle trap · 304 stainless and solid brass, brushed · 1¼ in stated · 200 mm dip tube · concealed cleaning opening · rosette included · 5-year warranty
A brushed stainless bottle trap that publishes a 200 mm dip tube — the closest thing to a water seal figure anywhere in this catalogue.
Best for: A wall-hung basin where the trap is on show and there is plenty of room beneath it.
≈ £48 / 40 €
