If you have seen flat bed trolley
 or any other you would have known wheels casters form their bases. When
 using a trolley you would have always thought that its structure 
decides the amount of weight it can carry. However this is not true, for
 it is the casters wheels which decide the amount of weight a trolley 
can be used to carry.
Besides the amount of weight there is one more thing 
you need to consider when buying two shelf trolley etc, and that is the 
surface on which you are going to use them. Wheels casters
 come in different varieties for smooth and rough surfaces. Check them 
to make the right buying decision with regards to flat bed trolley.
However if you need to also store your things, then 
you can always consider trolleys which also allow you to store your 
materials. And if you have specialized items to store and carry then you
 need to use special storages, like pelican cases can be used to 
transport electrical items which might get damaged due to water. For 
your tools you have the option to use plastic tool box with tray or without tray as the need may be.
There is no shortage of materials handling equipments
 for storage and transportation of your goods, no matter how big or 
small they are, no matter how heavy or light weight they are. However 
how good that particular flat bed trolley or pelican cases will be will 
depend on the type of trolleys or storage equipment you buy.
