In Europe, pitches are often more complex, and multi-pitch rigging is used extensively. Long drops are broken into smaller pitches. Re-belays and deviations are used to direct the rope away from areas of sharp rock and from water. Where rope rub cannot be avoided, rope protectors are installed. Traverses are often installed to allow the rigger to reach an area where it is possible to hang the rope with no rub. Since allowing the rope to rub against the walls is prevented, lighter ropes are used, usually 8-9mm thick. This has the advantage of being lighter and therefore more economical to carry on long or deep trips. Bobbin descenders are quicker to change over at re-belays and are also lighter to carry. Deviations are short length of tape or rope pulling the main rope to one side with a carabiner which can be conveniently unclipped and replaced to allow passing. Rope-walking techniques are less effective in cases of awkward passageways and for changeovers at rebelays.