EK-Quantum Torque STC 10/13 fittings are EK's new minimalistic 10/13mm (ID/OD) soft-tube compression fittings designed for use with various flexible soft tubing types such as PVC, EPDM, Norprene, silicone or any other type of compatible flexible tube. 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 is compressing the tubing wall underneath the ring, and this prevents the flexible tube from being pulled off the barb of the fitting. The grooves on the outside allow for easier hand tightening. The compression ring has cutouts in the 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-Quantum Torque series fittings are intentionally not painted on the inside to reduce the level of possible pollutants in the loop.