18km/ 770m D+ (ITRA-1 XS, UTMB® Index 20k) 10km/ 400m D+ hiking FT104 FT75 FT40 FT18 The UTMB® Indexis calculated for each of the 4 UTMB® World Series race categories 20K, 50K, 100K and 100M. A valid UTMB® Index is achieved by completing at least one UTMB® Wo...