The Braven IPX5 Waterproof Portable Bluetooth Speaker BRV-1 is retailing for S$228 from physical stores such as EpiCentre or Infinite (Apple Shops at Best Denki). Alternatively, you can also get it online from Ban Leong’s eStore.
Besides being a lightweight rugged Bluetooth speaker (346g), it also double up as a emergency portable charger using the built-in battery capable of outputting up to 1A. The 1,400mAh built-in battery will give you about 12 hours of music. Charging is done by micro USB and there is a 5 dots LED indicator to indicate the battery status.
