Detroit Diesel 6v71 or 12V71 Blower Core Good used core, good for rebuild not scored or messed up WARRANTY INFORMATION NO NEED FOR NEGATIVE OR NEUTRAL FEEDBACK. If there a problem, Contact us before leaving feedback. We try to be perfect but once in a while we make mistakes, but always take care of your e-mails and resolve all problems related with every part we sell. We want you completely satisfied and prefer that you contact us before leaving me any negative remarks. We try to package and ship next day but is not our only business. We may choose to reuse good boxes and be a Green seller. Money back guarantee if you are not happy with the part, you pay return shipping.