Whilst I appreciate that on auction site what you see is what you get, but, i did not expect this. Not a problem as I have a few spares, the question is this, is it due to mis-use of the stove or general wear and tear?
I reckon the only way that the hole could grow so large is the cap was used with a 'sacrificial ' coin (or similar) on top of it.... in an underburning situation. nick
It would of been hot enough to keep the flame burning straight up through the tube. Time to learn sil brazing