If you really want to know everything there is to know about classic expander read below.
- 14mm size (actually measures 12 mm) is to be used on lower section of ultralite poles (which should have diameter of 11.6 mm)
- 16mm size (actually measures 14 mm) is to be used on lower section of classic poles or middle section of the ultralite poles (which should have diameter of 14 mm)
- 18mm size (actually measures 16 mm) is to be used on middle section of classic poles (which should have diameter of 16 mm)
The classic expanders have been used by Leki for over 30 years and they are benchmark for all other systems to be compared against, they are still immensely strong and reliable.