Where can I use those magnet with hooks?

some metal board,For example:Fridge,Washing machines, metal doors, garages, metal shelves, ships and so on

What weight can it bear?

Maximum bearing 12 LB. There is basically no problem with conventional items, such as kitchen tools, chopping boards, shovels, spoons, water bottles, gloves, etc

I use it outdoors. Is it easy to rust?

No, its outer skin is covered with rubber coated, which is not easy to scratch and rust

I would like to hang kitchen ware,will it work well?

Of course, it can hold large power, 12 pounds holding power, kitchenware is a piece of cake.