Inner length:

21 yards long, 13cm

22 yards long, 13.5cm

23 yards long, 14cm

24 yards long, 14.5cm

25 yards long, 15cm

26 yards long, 15.6cm

27 yards long, 16.2cm

28 yards long, 16.8cm

29 yards long, 17.4cm

30 yards long, 18cm