These headset spacers are exactly what you need for adjusting your bike's handlebar height! The 28.6mm inner diameter fits most standard mountain and road bike stems perfectly. The aluminum alloy construction is lightweight but durable - no worrying about corrosion or damage. What's really convenient is the variety of thicknesses - you get 2mm, 3mm, 5mm, and 10mm spacers, so you can mix and match to get that perfect handlebar height for your riding style. Installation is straightforward - just slide them onto your fork steerer tube below your stem. The multicolor options are fun and let you add some personal style to your bike. I used these to raise my handlebars for a more comfortable riding position, and the difference was noticeable immediately. The quality is solid - the machining is precise with smooth edges and consistent sizing. They're compatible with MTB, road bikes, BMX, touring bikes - pretty much any bike with a standard 1-1/8 inch steerer tube. Whether you're building up a new bike or just adjusting your current setup, these spacers make it easy to dial in that perfect fit. They're affordable, well-made, and essential for any bike maintenance toolkit. Definitely recommend if you need to adjust your handlebar height or are building a bike from scratch!