How to create print device for printing specific size of label

Dear All,

My requirement is ,in selection screen : if i select equipment number and label size(as i mentioned below) it has to call corrsponding smartform and print the barcode with equipment number.

how to create print device as below for printing specific size of label.

Size of Label: 41.0 by 39.5

18.5 by 15.5

15.5 by 7.25

41.5 by 5.75