This is a neat and very helpful tool for those of you needing to get your compressed gas cylinders “hydro’ed”. Using Google Maps, all one has to do is type in their zip code and the map will provide locations within a 15, 25, and 50 mile radius of those companies that can either perform visual inspections and pressure testing. Although I will caution you… some of the businesses that pop up have a license/permit to perform inspections/tests but I am almost certain they do NOT provide this service outside their company. It appears that the map locations were done based on certificate holders and not necessarily those who perform this service for anyone needing testing done on their cylinders.