Using the symbol '-' in route will cause error

I want to route a URL like "http://localhost:3000/admin/product- details".I defined the route mapping in routes.rb:

map.namespace :admin do |admin|     # Directs /admin/products/* to Admin::ProductsController (app/ controllers/admin/products_controller.rb)     admin.product_details '/product-details(.:format)',                                 :controller=>"product_details", :action=>"index",                                 :conditions=>{:method=>:get}     admin.connect '/product-details(.:format)',                                 :controller=>"product_details", :action=>"create",                                 :conditions=>{:method=>:post}

  end

When I visit the URL,Rails throw a error: ActionController::RoutingError: No route matches "/admin/product- details" with {}

I visit http://localhost:3000/admin/product_details well.

Can you not use an underscore?