EK-Quantum Torque HTC 12 fittings are EK's new minimalistic 12mm hard-tube compression fittings designed for use with solid tubing such as Acrylic and PETG. With a non-intrusive, yet striking look, and with NO added branding at all. They can be complemented by interchangeable aesthetic color rings, and are an ideal choice for anyone and a perfect match with EK-Quantum series products. The locking ring prevents solid tube to be pulled out of the fitting by compressing the rubber gasket underneath the ring. The grooves on the outside allow for easier hand tightening. The compression ring has cutouts in EK Quantum signature shape allowing for the colored aesthetic ring to be shown. The colored rings are available in many colors and are screwed onto the fitting before the compression locking ring. The aesthetic rings are sold separately. The fitting barb and the compression rings are covered with a unique, high-quality satin black finish. Both are made of CNC machined brass and the seal is made quality rubber O-rings. Black EK-QuantumTorque series fittings are intentionally not painted on the inside to reduce the level of possible pollutants in the loop.