I installed a (model: SKC600MS/256G) in the ProBook 450 G2’s WWAN slot (normally for a mobile broadband card). The system recognized it immediately in BIOS and Windows 10 Pro.
Because M.2 2242 SATA drives are expensive per GB and harder to find, the smarter upgrade is to replace the main 2.5-inch hard drive with a standard SATA SSD. hp probook 450 g2 m2 ssd compatibility
2242 only . The slot is located near the Wi-Fi card and is too short for the more common 2280 size. I installed a (model: SKC600MS/256G) in the ProBook
Here is the critical specification: