Compatible With: M501dn [HPL4544]. NBD = Next Business Day HP provides quick replacement of your failed hardware unit the day after it goes down, if the problem can’t be resolved remotely. Offers a convenient, cost-saving alternative to onsite hardware repair for your HP product. Increase the return on your HP hardware investments and peace of mind. The longer the service plan you choose, the more reliable support you can expect from HP. Purchasing HP Care Pack service with HP product reduces total cost of ownership. HP Care Pack Services delivered through accredited network of partners or by an HP engineer ensuring the best possible service.