How we make it so durable and stable

When we go back in time everyone of us can remember the old, wooden ladder rungs. That was good solution in this kind of tool for many years. But definitely not the best one. Wood has accompanied us in construction since ancient times. But nowadays we invented better solutions to provide durability for ladder rungs. Now I use aluminum in tools like this. Aluminum is light what makes the ladder more flexible, easy to carry. The best part of it is aluminum is lighter and more durable than wood so we can ensure more safety by lower costs. Of course, it all always comes down to the safety of employees.