Snap-lock structure and pipe unit comprising the same

The connection structure has a coupling part (4) for connection to a second part. The coupling part has a peripheral wall (5) with integrated locking projection (7). This is moved into locking position to fix coupling part and second part in joint position. The locking projection has an engagement zone and a neighboring section with a U-shaped fold (9) in a peripheral wall. The engagement zone rises tongue-like out of the wall, from a root section (8). The structure is a blow-molded part.