The Brand-X External EC Straight Headset Pro M11 is a high-quality headset designed specifically for mountain bikes. With a 1 1/8 inch steerer tube diameter, this headset features a threadless external cup design for easy installation and maintenance. The sleek black colour adds a stylish touch to your bike, while the durable construction ensures long-lasting performance during your rides. Ideal for cyclists looking for a reliable headset that can withstand the challenges of off-road biking.