2021 Truck Index Single User Windows CD-ROM includes all three books, Gasoline, Diesel, and Import on one disk. All files are installed in PDF format and all models are bookmarked for easy reference. Software License issued with each CD-ROM is for a Single User on one Computer only. Adobe Acrobat 7.0 or later Reader Software is required. Adobe Acrobat Reader Copyright 1987-2021 Adobe Systems Incorporated. Quanity Discount: 3-6 disks $113 each, 7-13 disks $105 each, and >14 disks $98 each. Weight approx. 4 oz.