Simply Auto LE004 100cm Luggage Elastics, Pack of 2Roof loads are where a bungee cord earns its keep. Anything on a roof rack is exposed to wind at motorway speed, and wind gets under a load and lifts it long before the load itself decides to move. Holding it down properly takes a cord that reaches from one rail to the other with tension left in it.At a full metre, these are the longer ones. They span a roof rack rail to rail, cross a roof box, hold down a ladder or a length of timber, and take in a bike, a kayak or a load of garden waste on a trailer. Two in the pack, which is what most roof loads need at minimum, one across the front and one across the back.Simply Auto Luggage Elastics are made to BS AU 258:1995, the British Standard for elastic luggage restraints, and carry TÜV and GS approval. The elastic, the hooks and the join between them have all been tested by someone other than the manufacturer, which is more than most bungee cords can claim. On a roof load that is worth having, since a cord letting go at 70mph is a different problem from one letting go in a car park. The hooks are metal and grip a roof rail, rack rail, tie-down point or load bed anchor.Using them safely: Hook one end on first, then stretch the cord to the second anchor keeping your face and body out of the line of pull. A hook that slips travels fast, and a long cord travels further. Check the elastic before each use and replace any cord where the covering is split or the hook has worked loose. Bungee cords hold a load steady but they are not a substitute for proper ratchet straps on anything heavy.