The answer is multi-layer construction to make titanium thinner.

The "QUANTUM MINI driver" also features a TRI-FORCE face. A newly developed three-layer face, with a polymesh layered between titanium and carbon, allows for even thinner titanium. This maximizes the material's rebound force, significantly improving ball speed.

Over 59,000 face designs and more than 2.27 million simulations

The TRI-FORCE face, as its name suggests, has a three-layer structure. It was perfected after more than 59,000 face designs and over 2.27 million impact simulations. When the ball makes impact, pressure is applied to the hitting surface of the face, while tension is applied to the back. Therefore, titanium, which is resistant to pressure, is used on the hitting surface. We succeeded in making it thinner than the previous ELYTE series. Furthermore, on the back supporting the titanium, a thin layer of polymer mesh and a thin layer of tension-resistant carbon fiber are layered on top. This maintains durability while maximizing the rebound force of the titanium face, resulting in a dramatic improvement in ball speed.

The ballistic correction effect has also been greatly improved by AI design.

Callaway continues to utilize its long-standing AI-driven face design, resulting in even greater trajectory correction. This is because the titanium portion of the TRI-FORCE face has been thinned, allowing the face to flex more easily at impact, further enhancing the AI-designed control points. In particular, the range of spin variation is smaller than the previous ELYTE model, regardless of where the ball is struck on the face, making it easier to maintain optimal spin. For example, the ball is less likely to balloon on heel shots, and spin is not reduced too much on toe shots, resulting in consistent distance.

First OptiFit 4 with a mini driver

The "QUANTUM MINI driver" features a triaxial carbon crown and a titanium body. It comes in two loft options: 11.5 degrees and 13.5 degrees. A notable feature is the adjustable hosel. Unlike conventional models, it incorporates the "OptiFit 4" system, which offers increased loft and lie angle variations, similar to fairway woods and utilities, making it the first mini driver to feature this system. Sole weights are placed in two locations, front and rear, weighing approximately 2g and 7g respectively. The club length is 43.75 inches, which is 0.25 inches longer than the previous ELYTE MINI driver