There are a few options for GonG stems. A 14mm GonG fitting will accept a thread-on SS roasting tip using a silicone sleeve. An all glass roasting tube (14mm GonG) will accept a slide-in or dimple style SS roasting tip using a silicone sleeve. The slide-in or dimple style tips will have better air flow than the thread-on style. I can also do any of those three SS roasting tips in a 14mm or 18mm WonG or PonG. I just need to get some larger diameter poly rod for the PonGs.