1. [Easy Shifting, Smooth Ride]: Experience seamless gear shifting with these aluminum alloy 3x6/3x7 thumb shifters. Designed for 18/21 speeds, they ensure precise and easy shifting, allowing you to tackle hills, flats, or any terrain with ease. Perfect for mountain biking, city commuting, or leisure riding, they take your riding experience to the next level. 2. [Compatibility with Your Bike]: These shifters are compatible with handlebars with a diameter of 22.2 mm, suitable for a variety of bicycles, including mountain bikes, city bikes, leisure bikes, road bikes, and folding bikes. No matter how you ride, you can enjoy the convenience and performance of these versatile thumb shifters. 3. [Reliable Construction, Durable]: Made of high-quality aluminum alloy, these shifters can withstand the rigors of daily riding. The sturdy construction ensures durability and reliability, so you can rely on them for years to come. In addition, the included stainless steel inner cable (150 - 200 cm / 59 - 79 inches) is wear-resistant, ensuring smooth operation for a long time. 4. [Comfortable design, better control]: This thumb shifter is ergonomically designed for optimal comfort, allowing you to shift gears without removing your hands from the handlebars. The intuitive design ensures easy control and fast shifting, allowing you to focus on the road ahead. Whether you are navigating busy streets or exploring off-road trails, this shifter will keep you in control.