"穿著特种服装的" can be translated into English as "wearing specialized/special-purpose clothing" or "clad in specialized/special-purpose attire" (the latter being a more formal or literary expression).
Here are a few examples in context:
1、 The team members were all wearing specialized clothing for the extreme weather conditions.
（队员们都穿着应对极端天气条件的特种服装。）
2、 The workers were clad in special-purpose attire to protect themselves from hazardous materials.
（工人们穿着特种服装以保护自己免受有害物质的伤害。）