The red colour aids visual identification on the line.
The Water-Protection Rating and What It Means
This housing carries a JIS C 0920 Grade Level 7 rating, which corresponds to a water-protection level roughly equivalent to IPX7 — the connector can withstand temporary immersion in water when mated with the correct WPJ plug and properly sealed. That makes it a practical choice for outdoor lighting, garden equipment, or any harness that sees rain or washdown. The seal relies on the mating interface, so the plug half must also carry the same grade level.
The listing explicitly states contacts are not included. The crimp termination method gives a reliable gas-tight connection when the correct JST WPJ crimp terminal and tooling are used. Confirm the wire gauge range of the terminal matches your harness build before committing.