That should work, I have a similar device I use for sending audio from my phone to a 3.5 aux in. That's not a transmitter - that's a receiver. So far it has paired with anything I tried.
Just take out that silver adapter, plug your headphones into it, and pair it with your Oasis.
This is the one I've used:
https://www.amazon.com/gp/product/B013QJ0W8Q/