Under Para. 2 in the Computed Radiographic Package, they are requiring two (2) on site (NSWC Crane, IN) Preventative Maintenance (PM's) visits per year. The HPX-1 system does not require PM's as the only maintenance is occasional filter changes which the end user can easily do. This is provided in the installation/training portion. Moreover the three year extended warranty includes a free loaner HPX-1 shipped overnight should any service ever be required. The PM's would add considerably to the quotation and they are not necessary. We are familiar with other x-ray systems at Crane that do require them but this is not the case with the HPX-1.