Stata friends,

I've struggled with this one for a while and hope someone can help me. I have two datasets:

B_data
B PofB
0 1
5 2
O_data
O PofO
0 6
5 9
I wish to combine them to have every combination of B and O with associated Pof...That is,
B O PofB PofO
0 0 1 6
0 5 1 9
5 0 2 6
5 5 2 9
Can any suggest how I can do so? Thank you.

Glenn