The Shuttle PHD4 is a dedicated 3.5" hard drive rack kit designed specifically for Shuttle's 3-liter Slim XPC series, including models XH81, XH81V, XH97V, XH170V, XH110, and XH110V. This accessory enables the installation of a single full-height 3.5" HDD or SSD inside the compact chassis, expanding storage capacity without compromising the slim form factor.

This rack kit comes complete with a mounting bracket, a 3.5" HDD power cable, and screws to secure the drive firmly in place. Please note, when the PHD4 is installed, no other drives—such as a slim DVD drive or a 2.5" HDD/SSD—can be used simultaneously. Shuttle advises operating hard disks at ambient temperatures up to 40°C, recommending SSDs for applications with higher thermal conditions.

Optimized for Shuttle XH series slim PCs, the PHD4 provides a streamlined solution for users seeking additional internal storage in a small footprint while maintaining system stability and proper mounting.

For detailed technical specs and compatibility, visit the [Shuttle official product page](https://global.shuttle.com/products/productsSpec?productId=1863).