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Small black rectangular Bluetooth 5.4 adapter with USB-C port and 3.5mm jack

Ko-Star FJ-58RL-ED5F Bluetooth 5.4 2-in-1 Transmitter Receiver 280mAh 13/15h 3.5mm USB-C

SKU CH-C43K-X7Q03

Bluetooth 5.4 2-in-1 transmitter and receiver with 280mAh battery for 13h TX and 15h RX via 3.5mm jack

  • Channels1
  • ConnectorsUSB Type C
  • Remote Controlfalse
  • FeaturesFast Charging
  • Bluetooth 5.4 gives ultra-fast, low-latency audio
  • 2-in-1 switch toggles between TX and RX modes
  • 280 mAh battery delivers 13 h transmit or 15 h receive
  • Dual pairing keeps two devices connected at once
  • Pocket-sized 28.5×58×11.7 mm body with lanyard hole

Compact Bluetooth 5.4 Adapter

The Ko-Star FJ-58RL-ED5F is a pocket-sized 2-in-1 transmitter and receiver for wireless audio. It adds Bluetooth 5.4 connectivity to devices with a 3.5 mm jack such as TVs, PCs, or gym equipment. A simple slide switch selects TX mode for sending audio to headphones or RX mode for receiving audio from a phone or tablet. The tiny 28.5 by 58 by 11.7 mm body includes a lanyard hole for travel.

Sustained Battery Performance

A built-in 280 mAh cell delivers up to 13 hours in transmitter mode and 15 hours in receiver mode. The battery recharges through a USB Type-C connector that supports fast charging. This capacity lets the adapter last through long flights, gym sessions, or workdays without needing a mid-day top-up. Real-world runtime will vary with volume level and codec negotiation.

Interface and Connection Limits

The 3.5 mm analog jack is the only audio path, so digital or multi-channel formats are not supported. Bluetooth 5.4 handles the wireless link for a single audio stream at a time. The adapter pairs with two source devices but plays from only one, requiring manual switching. No remote control, microphone, or aptX branding is specified in the data.

Highlights

  • Bluetooth 5.4 gives ultra-fast, low-latency audio
  • 2-in-1 switch toggles between TX and RX modes
  • 280 mAh battery delivers 13 h transmit or 15 h receive
  • Dual pairing keeps two devices connected at once
  • Pocket-sized 28.5×58×11.7 mm body with lanyard hole

Specifications

BrandKo-Star
Part NumberFJ-58RL-ED5F
Channels1
ConnectorsUSB Type C
Remote Controlfalse
FeaturesFast Charging

Questions about this item

Will the 280mAh battery last through a full day of transmitting audio to my headphones?

The built-in 280mAh battery provides up to 13 hours in transmitter mode and 15 hours in receiver mode, rechargeable via USB Type C.

Do I need to supply my own 3.5mm audio cable to connect this adapter to a TV or PC?

A 3.5mm plug is integrated on the unit; you plug it directly into the AUX port of the TV, PC, Switch or other source.

Can I keep two Bluetooth headphones paired at once so my partner and I can listen together?

Dual connection support lets the adapter stay linked to two devices simultaneously for easy switching.

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