The Imperial DABMAN i510 BT is suitable for all speakers that can be connected to a hi-fi system, as the device has analogue audio outputs (stereo cinch RCA) and digital outputs (coaxial S/PDIF and optical TOSLINK). You can therefore use speakers that can be connected either directly to an amplifier or to an active speaker with corresponding inputs.
The device itself is a hybrid radio and network player that has no integrated speakers, but serves as a source for external speakers or hi-fi systems. For the best compatibility, you should choose speakers that match your existing amplifier or active speakers and that have cinch, optical or coaxial inputs.