third nut on the tank band

[do it easy]

I have a set of faber 98's with OMS tank bands. Each band comes with three nuts, and as I recall, the third nut is threaded on the BP side, but inside the tank band. I'm not the least mechanically inclined person, but what is this nut used for? It seems to me that you could do fine without it. I lost the original diagram that came with the bands, so I'm not even sure if this is just an extra nut. Aside from being an extra nut, the only thing I can think of is that it adds support when you wear the BP and doubles out of the water.

Do It Easy

 

[Henryville]

With what you're describing, there would not be a function for the third nut inside the band other than to prevent you from fully tightening the one on the outside of the band. Maybe it's a spare, or a way to more permanently assemble the rig without using wing nuts to attach the BP to the bands?

Anyway, bands are bands. See this link for a diagram and instructions:

http://www.diveriteexpress.com/library/doubles.shtml

I know OMS put a third o-ring on their cross-bar, but a third nut?