Aspire have this to say about the tank. "Nautilus 3S tank is the special version of Nautilus 3, it comes with an elegant metal honey comb tube, Nautilus 3S tank also uses Nautilus series coils emulates closely to Nautilus GT taste, which will provide you premium MTL experience and extreme flavour enjoyment." Not sure why they mention the GT as the only similarity with it appears to be it has a cage.