The "USB RGB Gaming & Multimedia Speaker A81" likely features USB connectivity for power and audio, customizable RGB lighting, high-quality sound suitable for gaming and multimedia, easy-to-use controls, and a modern design.

The K2039 LED speaker is a portable speaker that features LED lighting effects. Unfortunately, I couldn't find specific details about a product with that exact name in my current database. It's possible that it's a relatively new product or a niche item not widely documented. However, LED speakers typically combine the functionality of a speaker with LED lights, providing both audio entertainment and visual effects. These speakers often have different lighting modes, colors, and patterns that can sync with the music being played.