Extruded and CNC-machined from 6061-T6 aluminum alloy, Box One Cassette Spacer Kits feature a super lightweight minimalist design and provide anywhere from 1 to 10 millimeters of spacing adjustmentCompatible with Box One and Box Three Pro and Mini hubsEach set contains (2) 1mm, (1) 3mm and (1) 5mm spacerBlackUPC/EAN/GTIN: 639266088547