Monster Shock 30W IPX6 Waterproof Portable Bluetooth Speaker $20 at Amazon $20 $50 New price low. Amazon with Direct-sale has the Monster Shock 30W IPX6 Waterproof Portable Bluetooth Speaker for $20 with free shipping on $35+ or with Prime. Has an advanced Bluetooth 5.4 and up to 17 hours of battery life. $20 retail: $50 Posted by Faraday05/26/2026 at 10:46 AM PT