tube in gambit
 

hi.my geometry is a tube L=100 mm,OD=0.3 mm,ID=0.1 mm.and it is 2-D
how should i make it in gambit?
If i consider it axissmetry we will have L=100mm,OD=0.15,ID=0.05mm.
my problem is how can i define wall thickness which is aluminium.