Both are horizontal pivot mitering band saws built on the same rugged frame. The S-20P is semi-automatic: the operator loads each piece and the saw lifts, clamps, and cuts. The S-20A is fully automatic. Its cast iron shuttle multi-indexes up to 27″ per stroke, and the automatic PLC touchscreen stores up to 100 jobs with 20 in the queue, so the saw indexes, clamps, cuts, and repeats a full cut list on its own.