stery dartmoor astro zs44 zs56 ridehubThe Dartmoor Astro ZS44 ZS56 are high performance semi integrated headsets (zero stack) with a ZS44 upper cup and ZS56 lower cup. Made from lightweight, anodized aluminum with an ultra low profile top cap , they offer a modern look and top level functionality. Equipped with precision 45 45 cartridge bearings with an anti corrosion titanium coating and high density grease that protects against water and mud, the set includes two 7075 aluminum sprockets