BUF-4
BUF-4 is a bufferbot aboard the Axiom in WALL•E. One BUF-4 unit works with M-O, VAQ-M and SPR-A as a part of the sanitation crew to clean up the EVE probes after they return from Earth. Another BUF-4 unit is a reject shown in the Repair Ward.
His name is a play on the word "buffer".