The 
JBL Go 4
 is an ultra-portable Bluetooth speaker designed for on-the-go use, offering durability and improved sound over its predecessor, the Go 3. Key updates include a slightly larger size, the addition of a custom EQ via the JBL Portable app, and support for Auracast to connect multiple compatible speakers. 
Key features
Audio and sound: Despite its small size, the 
Go 4
 delivers surprisingly big sound with punchy bass, thanks to its 1.75-inch (45mm) transducer. While the sound quality is impressive for its size, it is a mono speaker, so it will not produce a stereo soundstage unless two speakers are paired together.
Battery life: The speaker offers up to 7 hours of playtime on a single charge. A new "Playtime Boost" feature can extend the battery life by up to 2 extra hours by optimizing performance for louder and crisper sound. It takes about 3 hours to fully charge the speaker.
Durability and design: The 
Go 4
 has an IP67 waterproof and dustproof rating, making it suitable for outdoor use, including poolside parties and beach trips. The body is partially made from recycled plastic and fabric, and it features a redesigned integrated loop for easy carrying. It also floats in water.
Connectivity: It features Bluetooth 5.3 and includes Auracast technology for multi-speaker connections. You can pair two Go 4 speakers for stereo sound or wirelessly connect to other Auracast-enabled JBL speakers for a larger soundstage.
JBL Portable App: The addition of app support allows users to customize the sound with a 5-band custom equalizer (EQ). You can also use the app to check battery status and access the Playtime Boost feature.