UNIFORM case sealers are setup to receive the same size box, time after time. Uniform case sealers are adjustable within a range of case sizes and can usually be switched over to another carton size fairly fast.
RANDOM case sealers can seal a variety of case sizes on the fly. As the machine completes one case, it adjusts automatically to the next size box on the line. The side belts will move inward or outward automatically and the height of the tape head will automatically adjust as needed.