Amazon.com: PcProfessional Screen Protector (Set of 2) for HP ProOne 400 21.5" All-in-One Touchscreen Desktop Anti Glare Anti Scratch filter radiation+ high quality microfiber cloth : Electronics
HP ProOne 400 G1 19.5 in All In One Desktop Computer Intel i5 4th Gen. 8GB
HP ProOne AiO 400 G2
HP ProOne 400 G1 21.5 All-In-One i3-4360T 3.2GHz 4GB 500GB [K1K35UT] - $819.99 : Professional Multi Monitor Workstations, Graphics Card Experts
HP ProOne 400 G3 - All-in-one - no CPU - RAM 0 GB - no HDD - no graphics - GigE - monitor: LED 20" 1600 x 900 (HD+) - CTO - Walmart.com
Westcoast - HP ProOne 400 G6 20inch Intel® Core™ i5 49.5 cm (19.5") 1920 x 1080 pixels 8 GB DDR4-SDRAM 256 GB SSD All-in-One PC Windows 11 Pro Wi-Fi 6 (802.11ax) Black
HP ProOne 400 G1 All-in-One Intel Core i5 4590T (2.0 GHz) 4 GB DDR3 500 GB HDD Windows 7 Professional 64-Bit (available through downgrade rights from Windows 8.1 Pro) - Newegg.com