Power outages are a constant problem where I live, so I finally decided to buy a new UPS. However, the official WD list of compatible Uninterruptible Power Supply devices is dated and incomplete.
Experience has taught me that bigger is better when it comes to choosing a UPS, so I decided to purchase an APC model SMC1500C. It’s not on the official WD list of supported UPS devices, but it works perfectly regardless.
The APC SMC1500C is rated to handle about 900watts, which is definitely overkill for the modest power requirements of the PR4100, but I also have a server to protect, and the added run time is nice to have when needed.