Comparison : Item # P21H20, CAS Contractor Series Electric Reciprocating Air Compressor
Item # P21H10, CAS Contractor Series Electric Reciprocating Air Compressor
Item # P31H21, CAS Contractor Series Electric Reciprocating Air Compressor
Item # P31H11, CAS Contractor Series Electric Reciprocating Air Compressor
Item # P51H12, CAS Contractor Series Electric Reciprocating Air Compressor