What spikes can I wear for cross country?

ASA's spike rule (ASA Rule 25.19.1, following World Athletics shoe rules) applies:

• The part of each spike sticking out from the sole or heel may be no longer than 9mm (12mm is allowed only in high jump and javelin).
• At least the half of each spike nearest the tip must fit through a 4mm square gauge.
• If the venue operator sets a shorter maximum, that limit applies.

ASA notes that pyramid-shaped spikes give grip on grass, needle spikes suit hard surfaces, and blanks can fill unused spike holes.