From the manufacturer's official website:

NEWTON 26 stem is built in 2024 T3 aluminum alloy and CNC machined. It is a refined designed, strong and ultra-light. Suitable for 28,6 mm steerer tube or, using the sleeve, for 25,4 mm steerer. Titanium 6 Al/4 V hardware.

Technical Data:

• Front clamp diameter (bar bore): 26,0 mm
• Fork steerer diameter: 28,6 mm (1 1/8"); 25,4 mm (1")
• Tightening torque: (5,9 ft.-lbs)(71in.-lbs)
• Finishing: mat black anodized with silver anodized front clamp
• Weight: 125 grams (4 1/4 oz.)

For more information, please visit this product's webpage.