The tool is a balloon.
This geocache IS at the posted coordinates. The puzzling part is trying to open the container.
The cache is very obvious, in bright colors and in plain sight once you get to GZ. The trick is not to find it, but to open it. For this task, you will need to bring along a special tool. There will be hints throughout the page as to what kind of tool this is. (The tool might be a little expensive, due to inflation.) PLEASE DO NOT TRY TO FORCE THE CACHE OPEN—YOU ARE RISKING BREAKING THE MECHANISM INSIDE AND RENDERING THE CACHE INOPERABLE.
When you arrive at GZ with your tool, it will be evident what you're supposed to do with it. Performing this task will present some challenges—use your creativity! You can do it! When the cache is ready to open, you will hear a small clink. You will then have to pull the door pretty strongly in order to pop it open.
Once you've opened the cache, feel free to trade some SWAG! Just make sure you don't leave anything that would obstruct the opening/closing of the door. Also, if you leave a trackable in the cache, make sure it has something attached that will prevent it from slipping through cracks in the cache. There is one trackable in the container to start off.
Funny story: while placing the cache, I dropped it in the creek. The insides of the cache might seem a little damp for the first couple finders. Fortunately, the log was in a waterproof tube so it was preserved! Moral of the story: store your logs in watertight containers!
Additional Waypoints
FN8RZKA - Final Location
N 40° 05.477 W 105° 10.002
P08RZKA - Parking Lot
N 40° 05.352 W 105° 10.124
A good place to park.