I think this one is for 2 numbers in 1 phone (I can be wrong). The 2 SIMs will attach to 2 different phone numbers in the same physical phone.
So, some people have 2 different numbers say for personal and work, they can use the same physical phone for those.
OP wants 2 phone with 1 number. I am not sure if you can clone a SIM card, I think there is a way.
Then you can put the 2 SIM card into 2 different phones, those 2 phones suppose to have the same number.
Now, I am not sure how they manage which phone will ring, though.
See the difference?