3D file creation

My project requires a 3D file to print a 3D design that can be used to make a silicone mould. The 3D file needs to be in either STL, OBJ, or FBX file formats. I already have a clear design in mind, and the model only requires basic level detail. If you think you have the expertise to help with this project, please get in touch with me.
I have attached what I am looking to recreate and can provide the image file and dimensions.