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Black 120mm full-copper radiator, 25mm thick, two G1/4 ports, 15 FPI fins

Alphacool

Alphacool NexXxoS ST25 Full Copper 120mm Radiator 25mm Black 14352

SKU CH-1SAE-SNQE4

A full-copper 120 mm radiator with 15 FPI fin density and dual G1/4 ports for high thermal conductivity

  • TypeRadiator
  • Full copper construction delivers superior thermal conductivity at 400 W/(mK)
  • 15 fins per inch balances airflow and cooling capacity for quiet operation
  • 5 mm slim profile fits tight chassis spaces without sacrificing performance
  • Dual G1/4 ports enable flexible loop routing in any orientation
  • 120 mm single-fan design simplifies integration into compact custom loops

Copper Radiator for Custom Loops

The Alphacool NexXxoS ST25 is a 120 mm radiator built entirely from copper, including the end chambers, water channels and cooling fins. It fits a single 120 mm fan and uses two G1/4 ports for integration into custom water-cooling loops. The slim 25.5 mm thickness suits builds where space is limited.

Thermals and Airflow

Copper’s 400 W/(mK) conductivity outperforms aluminium’s 236 W/(mK), giving the core its performance edge. A fin density of 15 FPI keeps airflow resistance low so the radiator works well with quiet, low-pressure fans. The serrated fin surface increases turbulence to maintain cooling capacity without demanding high fan speeds.

Build-Grade Construction

Full copper construction eliminates mixed-metal corrosion risk and removes the need for specialised coolant additives. Standard G1/4 threads accept any common fitting without proprietary adapters. The black finish is applied over the copper body, leaving the thermal path unchanged while matching dark-themed builds.

Highlights

  • Full copper construction delivers superior thermal conductivity at 400 W/(mK)
  • 15 fins per inch balances airflow and cooling capacity for quiet operation
  • 5 mm slim profile fits tight chassis spaces without sacrificing performance
  • Dual G1/4 ports enable flexible loop routing in any orientation
  • 120 mm single-fan design simplifies integration into compact custom loops

Specifications

TypeRadiator

Questions about this item

How do I install the 120mm radiator and what step is often missed?

Mount the 151 x 120 x 25.5 mm radiator with a single 120mm fan, then connect tubing to the two G1/4" ports; the step often missed is tightening both ports evenly to prevent leaks.

What maintenance will the copper radiator need later?

Flush the loop annually and replace coolant to stop oxidation inside the pure copper channels and fins; inspect the 15 FPI fins for dust and clean with low-pressure air.

What limit appears first during sustained load on this 25mm slim radiator?

The 25.5 mm thickness caps fin surface area, so heat-soak arrives sooner than on thicker radiators; fan speed must rise to move enough air through the 15 FPI fins.

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