Which brand/model USB Keyboard with mouse tab works for TS-251D?

[ed]

Here is what Qnap users are saying:All keyboard, mice, pointer, trackpads, and combos coming with a USB human interface device class (USB HID class) dongle are workable.Not workable are ie. pure Bluetooth devices intended to be associated with a host-based Bluetooth stack, for notebooks, for iOS or Android devices.I hope this helps.