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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

  • Audio channels1
  • Connection typesUSB Type C
  • Key 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.

How it compares

Measured against everything we stock in Wi-Fi & Bluetooth Audio Devices, at today’s prices. Recalculated every night.

Price $25.99
Cheaper than about 87% of the 297 comparable items (median $63.99).

Specifications

Product
Brand nameKo-Star
Part numberFJ-58RL-ED5F
Audio & video
Audio channels1
Ports & slots
Connection typesUSB Type C
More details
Remote controllerNo

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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