B, C and D represent the Beacon Battery Code. The DK120 beacon label has a box which lists the code of the battery. Code B or D are considered dangerous goods, which requires hazmat shipping. Code C is not considered dangerous.
P/N 810-2007/K battery kit is for DK120 Beacons that list battery as Code B or D on the beacon label.
P/N 810-2008/K battery kit is for DK120 and DK140 Beacons that list the battery as Code C.
There is a size difference between the two battery kits; they can not be interchanged.