This concert dark silver Luthier classical guitar strings set 35 is a medium to hard tension set. The basses are constructed with a slightly harder alloy and look less brilliant compared to ordinary nickel plated bass strings (hence the name dark silver). Due to this alloy the basses retain their tone longer and sound more profound. This longer lifespan is for most guitarists the reason for choosing this set. The tension is medium hard, but feels quite sturdy, so rather as hard tension.