This is a convenient storage solution for storing the frame shifting wheels on a Springfree trampoline. These should have come with the wheels for the factory for convenient storage. There is a small hole to provide additional security for these hooks by using a zip-tie to secure the wheel holders. The ideal location is to put these near where you use the wheels. Print in PETG since these are outdoors (I'm using PETG-CF from Matter3D). These have been tested for multiple seasons and hold up perfectly.