MonsterXK (97% positive lifetime feedback) via Amazon is offering its Adventurer Force Waterproof Bluetooth Speaker for $54.99 shipped with the code NG323XPV at checkout. Down 50% from its normal going rate, today’s deal marks a new all-time low that we’ve tracked and is the best available. This speaker delivers up to 40-hours of playtime paired with Bluetooth 5.0 technology. Wireless isn’t the only input available here, however, as you’ll also find aux 3.5mm, microSD, USB, and even a microphone plug on this speaker. It’s IPX7 waterproof, meaning you can take it to the beach or pool without worrying about it getting wet. Rated 4.6/5 stars.