These particular ones are Waterslides, for future reference there seems to be an industry standard to make all Waterslides have a blue backing (excluding some Bandai ones included with older MGs that are completely clear and come with a separate piece of white paper for a backing) and all dry-transfer decals to have a light yellow-green backing. I haven't ever seen any in either category that deviate from that color-coding, but there's always a tiny chance that a particular set might not so it's good to double check anyway.