用塑料夹 meaning in English

in plastic binder

Clamping closures of plastics for telecommunication cables with metallic conductors and optical fibres - requirements and tests
金属导线和光纤通信电缆用塑料夹紧套管.要求和试验
Please do not bind your application materials together or place materials in plastic sheet protectors . these bindings do not fit into our files , and we throw them away
是不能绑在一起，又不能用塑料夹，那用什么装材料？大信封吗？什么样的信封？