A coupling (or a coupler) is a mechanism for connecting rolling stock in a train. The design of the coupler is standard, and is almost as important as the track gauge, since flexibility and convenience are maximised if all rolling stock can be coupled together.
Niumba is a rental apartment directory owned by the TripAdvisor Media Group. The website provides around 62,000 private holiday homes, 79% of which are located in Spain. Niumba's business model is based on putting those who wish to rent their homes in contact with travelers.