i once tried Z's prop and sust. i would load the needle with prop and when i would push the air out and have a lil prop drip out and slide down the needle for lube i could smell it like some sort of medicinal substance, very much like my experience with hg-gear in mexico. the prop worked awesome for me back then. oh, and im not trying to start anything with u if yours doesnt smell like mine did, just saying my experience with it.