The term UWA generally stands for 'ultra wide angle'. This includes all eyepieces, which have a very large apparent field of view in the range of 70° to 100°. These include, for example, the famous Nagler eyepieces with eight lens elements.
If you experienced tunnel vision when observing with Plössl eyepieces, here you are rewarded with a large field of view. As if you were taking a stroll among the stars, the experience is also known as the ‘space-walk effect’.