Belkin's "Boost Charge Pro 2-in-1 (15 W)" is compatible with devices using the Qi standard, but is not specifically optimised for Samsung phones such as the Samsung S23 Ultra.

- This wireless charger uses Qi and Qi2 technology, which means it can charge Qi-compatible devices, including some Samsung models.
- However, the maximum charging speed for Samsung phones is typically 10W with standard Qi chargers, and some models can support up to 15W with specific Samsung chargers.

So, yes, the Samsung S23 Ultra can be charged with this charger, but the maximum charging speed could be limited to 10W.