There are a number of different types of pheromone traps on the market, but they all work in roughly the same way.
In this video showing how to setup a trap the pheromone is in a thick liquid state, with other manufacturers it may be in solid stick form. The pheromone used in the demo lasts for about 3 months before you have to add more and there is enough included for 6 months cover (this should cover a year as the months start appearing in mid to late March and are usually gone by November). More pheromone can be purchased separately so just take the traps in during the winter and put them back out the following year with a new supply of pheromone.
Some traps also have water in the base where the trapped moths are collected. In this case the design doesn’t have water and there are drain holes to let water out if it were to get in. There is also a cylinder in the clear plastic to allow the trap to be mounted on a bean pole rather than being hung up.
The trap in this demonstration, Bayer BuxaTrap, was bought from Amazon.co.uk but other traps can be purchased for around the same price of £25 to £30 each.
Related story in the news section of the EBTS UK website