Sony’s handheld PlayStation model that omitted a UMD drive was the PSP Go.
The PSP Go was introduced in 2009 as a smaller revision of the PlayStation Portable. Instead of using the original PSP’s Universal Media Disc drive, it stored games downloaded from the PlayStation Store in internal flash memory or on Memory Stick Micro media. Its screen slid upward to reveal the controls beneath it.
The change made the PSP Go lighter and more compact, but it also meant that owners could not use their existing physical UMD collection directly. The earlier PSP-3000 retained the UMD drive, while the later PlayStation Vita used a different proprietary game card format. Those distinctions are common sources of confusion when comparing Sony’s handheld models.