Trevor, I have been using a Smith's Little Torch with Oxy-Acetylene
for years. When I purchased it, it came with 5 tips, #'s 1 - 5. I
have since added a couple of larger tips but find that for most of my
work I use the #3 & #4 tips. I don't think that I have ever used the
1 tip. I recall reading in the original instructions that with the
1 tip you could solder or braze a .001" wire. Never tried that but
if you want a really small tip that would be the one. The #1,2, & 3
tips have synthetic ruby orifices. Hope that this helps.