Irin yika jẹ igi gigun, irin to lagbara pẹlu apakan agbelebu ipin.Awọn pato rẹ jẹ afihan ni iwọn ila opin, ẹyọkan mm (mm), gẹgẹbi “50mm” tumọ si iwọn ila opin ti 50mm irin yika.