Variable Speed Zebra- ECM Diagnostics Factory Warranty only available from Airstar Supply , the ONLY Approved Zebra Instruments Vendor Microprocessor Controlled, but Easy-to-Use; only 4 switches. Rugged Case with Carry Handle and Lead Storage Compartment 2 Instructional DVDs Included, plus an Owner's Manual GE, who makes alargeshare of these motors, reports that 41% of the motors returned to their factory actually have "no problem found". That means someone made an expensive mis-diagnosis; it also meand the real problem has not been corrected by replacing the motor. Almost any mistake in diagnosis on an ECM system will cost much more than this tool does!