The special shape of the offset walking stick, centres your weight correctly over the shaft, providing maximum support. It is also known as a "swan neck" The quad cane offers all the same features as the offset cane with the added advantage of being self-standing.
You can purchase spare rubber feet on the accessories > ferrules page. Both types of walking sticks have sponge covered handles to make them more comfortable. You can purchase replacement sponge handle covers on the walking sticks accessories page too.