This shimano ultegra 6800 tubeless ready rear wheel uses the proven technology of the top of the range dura ace but at great value the rim is an asymmetrical tubeless ready so you can use tubed tyres as well there are 16 stainless steel bladed spokes on the front and 20 spokes on rear that has a special wide flange hub design that with the asymmetrical rim results in a stiff and stability wheel the hubs use labyrinth and contact sealing the low friction seals effectively shut out water mud