About this item 11 Pieces: The package includes 11 pieces bicycle headset spacers in 6 sizes, 3 x 2 mm, 2 x 3 mm, 2 x 5 mm, 2 x 10 mm, 1 x 15 mm, 1 x 20 mm. Suitable of most bicycles, road bikes, mountain bikes, MTB, BMX High quality: Made of aluminum alloy with improved CNC process, lightweight, rust-proof, which can ensure a longer service life Multiple Size: There are 6 sizes: 2mm/3mm/5mm/10mm/15mm/20mm, you can choose different sizes or make a variety of combinations to adjust the height of the headset stem, so that you can be more precise height adjustment Suitable for: Suitable for 1-1/8″ (28.6 mm) bicycle front stem fork. Lightweight and making riding easier Compatibility: Bicycle Headset Spacer Set inner diameter is 28.6mm, 1-1/8″ headset spacer set