There are five different versions of the Roku 2. I believe the voice remote will only work on two of them (model number 2720 and 4210), although that first one could be a maybe.
Just be aware that of all versions, the 4210 is the only one that Roku still supports, and it's likely going to lose support not too much longer. It's now ten years old (and the others are even older) and doesn't have the hardware necessary for the latest channels/apps. You should really consider replacing your Roku 2 with a newer model.
Dan
Roku Community Streaming Expert
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