Based on common naming conventions in the simulation game community, the components of the filename likely represent:
: The primary data files containing the 3D meshes, textures, and coding for the item to appear in-game. SSP-7-18-REM_tubwheat.zip
: Often included by the creator to specify installation paths (usually Documents/EA Games/The Sims 2/Downloads ) and any "mesh" requirements. Based on common naming conventions in the simulation