Review on 🔊 18oz Stainless Steel Tumbler with Bluetooth Speaker - Vibe Speaker Tumbler Upgraded with Long-Lasting 1000MaH Battery for 8 Hours Playback Time, IPX67 Water Resistant, Ideal for Beach, Camping, or Golf by Stuart Rasmussen

This mug is a great idea and the speaker sounds pretty good considering it's attached to the bottom of the mug, but the mug I received has a loose piece of metal sealed inside the mug. Every time I pick up a cup and tilt it to drink, you can hear the metal sliding inside, which is REALLY annoying given that it's absolutely impossible to get it out. When you shake the cup, it looks like a rattle.