Maybe one of these similar products would be of interest:-
Acoustic Guitar Strings By Martin & Co, M150 80/20 Bronze Medium 13-56
Martin 3 PACK Bronze Acoustic Guitar Strings Custom Light 11 - 52
Acoustic Guitar Strings By Martin, M175 Custom Light 80/20 Bronze 11/52
MARTIN ACOUSTIC GUITAR STRINGS LIGHT 12-54 CHEAPEST ON EBAY ( LOOK )