• 1.Product Overview
• 2. Key Specifications
• 3. What's in the Box
• 4. Device Compatibility
• 5. Installation Guide
  • Method 1 — Connect via 2.4GHz USB Receiver
  • Method 2 — Connect via Bluetooth
  • Multi-Device Switching
• 6. How to Use (by Scenario)
  • Laptop → Keyboard (USB Receiver)
  • Laptop → Keyboard (Bluetooth)
  • Tablet / Phone → Keyboard
• 7. Battery & Charging

1.Product Overview

Bubble 4.0 is a premium wireless rechargeable keyboard designed for comfortable and quiet typing across multiple devices. It supports three Bluetooth connections and one 2.4GHz USB receiver connection, allowing users to switch between devices instantly without reconnecting every time. It also features an integrated rechargeable battery and low-noise keys for everyday productivity.

The keyboard supports:

• 2.4GHz Wireless via USB Receiver
• Bluetooth Multi-Device Connectivity (up to 3 Bluetooth devices)
• Rechargeable Battery (USB Type-C)
• Silent & Comfortable Typing
• Windows, macOS, Android & iOS Compatibility
• Plug & Play Operation

2. Key Specifications

Specifications are based on the official product information and support documentation.

3. What's in the Box

• 1 × Bubble 4.0 Wireless Keyboard
• 1 × 2.4GHz USB Receiver
• 1 × USB Type-C Charging Cable
• 1 × User Manual

4. Device Compatibility

Bubble 4.0 works with devices supporting Bluetooth or USB input.

Compatible Devices

• Windows Desktop & Laptop
• macOS / MacBook
• Android Phones & Tablets
• iPad
• iPhone (Bluetooth)
• Smart TVs (if Bluetooth keyboard is supported)
• Mini PCs

Supported Operating Systems

• Windows
• macOS
• Android
• iOS

7. Installation Guide

Method 1 — Connect via 2.4GHz USB Receiver

Step 1 – Charge the Keyboard

Charge the keyboard using the supplied USB Type-C cable before first use.

Step 2 – Turn ON the Keyboard

Move the power switch to the ON position.

Step 3 – Insert the USB Receiver

Remove the USB receiver from the keyboard and plug it into your computer.

Step 4 – Select 2.4GHz Mode

Press the dedicated 2.4GHz shortcut (Fn + Receiver Mode key, depending on model).

Step 5 – Automatic Connection

The keyboard connects automatically.

No drivers or software are required.

Method 2 — Connect via Bluetooth

Step 1

Turn ON the keyboard.

Step 2

Press and hold one of the Bluetooth keys (BT1 / BT2 / BT3) until the LED begins blinking.

Step 3

Enable Bluetooth on your computer, tablet, or phone.

Step 4

Search for:

Portronics Bubble 4.0

Tap Connect.

Step 5

The LED becomes steady once pairing is complete.

Multi-Device Switching

Bubble 4.0 can remember multiple paired devices.

Example:

• BT1 → Laptop
• BT2 → Tablet
• BT3 → Phone
• 2.4GHz → Desktop

Press the corresponding shortcut key to switch between connected devices.

8. Battery & Charging

• Recharge using the supplied USB Type-C cable.
• Connect to a USB charger or computer USB port.
• Charge fully before first use.
• The keyboard automatically enters sleep mode after a period of inactivity to conserve battery.
• Press any key to wake the keyboard; it reconnects automatically within a few seconds.