You are looking for a container with a screw-off top. This container is affixed via two magnets, one on the bottom and one on the top. When you replace the cache, please try to make sure that both magnets are making contact with the metal. Log only. BYOP.
Lots of roads have curves, some more pronounced than others. Here's one on Southeast Central Parkway in Stuart. It's a bendy one near Poppleton Creek Park.
Here are links to the rest of the caches in the "A Curve In The Road" series: A Curve In The Road #1, A Curve In The Road #2, A Curve In The Road #3, A Curve In The Road #5, A Curve In The Road #6, A Curve In The Road #7, A Curve In The Road #8, A Curve In The Road #9, A Curve In The Road #10