You have to get them through a exterminator, or an exterminator supply willing to sell them to you. I believe the web site for In2Care has a “where to get them” page with zip-code search.
Exterminators will typically want to do the install themselves, but we found one happy to just sell me the supplies. There are videos on line about how to set them up - its not hard.
Once caution - curious raccoons in our yard like to mess with them - they wet the mesh and spoil the trap. They can burn through your seasons supplies in a week.
