Measured with Speedtest.net (real speed) the JRS Eco-wifi 01A offers 25 Megabits per second (Mb/s) while the JRS Eco 100 D1 and D2 models offer 400+ Mb/s. To achieve the maximum speed that your internet subscription supports, you need to choose the Eco-wifi model that is at least as fast as that. You can find out your internet speed on Speedtest.net.
The Eco 100 D1 and D2 models are dual band, which means they emit on two frequencies: 2.4 and 5 Gigahertz. This allows for higher throughput speeds and for mitigating interference from neighboring wifi routers. You may turn off one of these if you want to minimize radiation.
For more details see the JRS Eco-wifi product comparison table.