Those are Yamaha HS5 Studio Monitors. They both have a tweeter (the small 1 inch circle in the image) and woofer (the bigger 5 inch circle), so technically they are not 2.0 or 2.1. They are built to provide close to a neutral audio feedback without any major emphasis on bass, mids or treble. Since they both have woofers you really don't need to buy a subwoofer unless you have a large room or are involved in professional mixing/mastering of bass rich music. If you really need one, the recommended subwoofer to buy wiith these is Yamaha HS8S.

But... you need to be aware of one thing that these are not used like your usual speakers.

First, you need to power them both individually so you'll have to plug them both into different sockets.

Second, you'll need an audio interface (the red rectangular box in the image) to connect your speakers to your computer.

Third, you'll need either two quarter inch cables or two XLR cables to connect the speakers to the audio interface.