Anker's SoundCore 2 is a popular mini Bluetooth speaker on Amazon. It costs $35 (£42 in the UK, AU$99 in Australia), plays pretty loud for its small size, is water-resistant and has excellent battery life. That's all good -- and the SoundCore 2 is a perfectly fine little wireless speaker -- but it doesn't sound as good as the similarly priced and can't handle certain bass frequencies at higher volumes.
Cosmetically speaking, the 11.2-ounce (318g) SoundCore 2 has a straightforward, low-frills design that's highlighted by a soft-to-the-touch rubberized finish and nice, big buttons on top for power, volume control, pause/playback and Bluetooth connectivity. Slightly bigger than Anker's original SoundCore, it sounds slightly better, with a little better bass response, and adds the aforementioned splashproofing. (With their prices so close, there really isn't any reason to buy the original SoundCore at this point even though it remains on sale).
I had no problem pairing it and the wireless range was good (Anker lists it a 66 feet or about 20 meters). A rubber gasket covers the USB charging port and auxiliary input, which allows you to connect non-Bluetooth devices. Additionally, there's a built-in microphone for making speakerphone calls, but don't expect business-class performance.