Three, sealed cartridge style, bearings; two on the chainring side & one on the non-drive side. Weighs just 220 grams; only 30 grams more than Record.17 mm cro-moly steel, 102 mm hollow spindle fits 8, 9 & 10 speed Campy Record & Chorus cranks from 1995 to present. Unique taper is not interchangeable with Shimano. Removable cups are machined from 7000 series aluminium alloy & are easily replaceable. Comes with British (1.37 inches x 24 threads per inch) or larger diameter, Italian cups (36 mm x 24 threads per inch). Spindles are identical & always 102 mm long. Fits either Record or Chorus square taper cranks