Hey there ! Was wondering if anyone knows a source for titanium or stainless steel beads/balls in the size of 3 or 4 mm ? I heard it mentioned few times in various thread so if someone has done the reasearch already please share. I have a concept in the works that allows me to have metal ,since my heater is not in direct contact with the balls . It works great with the glass ones but i dont see why not to satisfy the curiosity for the metal ones.