Hammer Box is in Cájar. Tap the map or the "Get directions" button to see the exact location and the route from your position.
Yes, Hammer Box's official website is hammerbox.es. You'll find the direct link in the "Website" section of this listing.
On this listing you can see "Other gyms nearby" right below, sorted by proximity. You can also open the full gyms in Cájar page for the complete map ranked by distance from your location.