We take cryptocurrency — so the coins you hold can buy real hardware.Pay in crypto, spend it on real hardware. Free insured shipping worldwide over $399. Plain, unbranded boxes, sent from Germany.Free insured shipping over $399. Your rate is locked for 30 minutes once checkout opens.Rate locked 30 minutes. Every item sealed, serial-checked and covered by a 24-month warranty.Sealed, 24-month warranty.

Saved items Sign in
Brass barbed reducer fitting 1/2 to 3/8 inch, metallic gold finish

Barrow Mods

Barrow Mods TBJB3-4 1/2" to 3/8" Barbed Reducer Fitting

SKU CH-ZFZV-M08VS MPN TBJB3-4

Brass barbed reducer joins 1/2" to 3/8" ID soft tubing securely without requiring hose clamps

  • FeaturesReducer fitting to join up 1/2” ID to 3/8” ID soft tubbing
  • Connects 1/2" and 3/8" ID tubing in one fitting
  • Barbed ends grip soft tubing securely without mandatory clamps
  • Optional hose-clamp groove adds extra leak protection
  • High-quality brass construction resists corrosion in liquid-cooling loops
  • Straight reducer design keeps custom loops compact and tidy

1/2" to 3/8" Barbed Reducer Fitting

The Barrow Mods TBJB3-4 is a brass reducer fitting designed to join 1/2 inch ID soft tubing to 3/8 inch ID soft tubing in a custom liquid cooling loop. Its barbed ends grip the tubing walls directly to create a secure seal without mandatory hose clamps. The fitting enables builders to transition between two common tubing sizes within a single circuit.

For loops mixing tubing diameters

This fitting suits builders who need to connect 1/2 inch and 3/8 inch soft tubing runs in the same loop. It is not intended for rigid tubing, compression fittings, or push-fit systems that require specific locking mechanisms. Users relying solely on clamp-free security should verify barb retention under their specific pump pressure. It does not adapt differing thread standards or connect dissimilar tubing materials.

Dual-barb size transition

The single deciding specification is the dual barb sizing: one end accepts 1/2 inch inner diameter tubing while the other accepts 3/8 inch inner diameter tubing. This exact size pairing determines whether the fitting matches the two tubing sizes present in the loop. Brass construction provides corrosion resistance but the barb geometry dictates compatibility.

Highlights

  • Connects 1/2" and 3/8" ID tubing in one fitting
  • Barbed ends grip soft tubing securely without mandatory clamps
  • Optional hose-clamp groove adds extra leak protection
  • High-quality brass construction resists corrosion in liquid-cooling loops
  • Straight reducer design keeps custom loops compact and tidy

Specifications

BrandBarrow
ModelTBJB3-4
FeaturesReducer fitting to join up 1/2” ID to 3/8” ID soft tubbing
Part NumberTBJB3-4

Questions about this item

How do I confirm the Barrow TBJB3-4 fitting is sealing correctly after installation?

Pressurise the loop and watch the barbed joints; no coolant should escape from the 1/2" or 3/8" connections.

What comes with the TBJB3-4 reducer and what must I supply?

The box contains the brass reducer fitting only; you must provide 1/2" ID and 3/8" ID soft tubing, plus optional hose clamps if desired.

Which version of the TBJB3-4 should I choose for my loop?

Only one version exists — a 1/2" to 3/8" barbed reducer — so select it when your loop mixes those two tubing sizes.

Also in this aisle

People compared these

Same shelf, same checkout — eight coins and a 30-minute rate lock.