passing same params through several controllers

Model Product ... #has weight end

ProductController def list   top = params[:top] #positive integer   #select how many product based on weight from highest to lowest as much as 'top' element   #for example: list?top=10, only list the top 10 heaviest product   ... end

def edit   ... #edit product   ... #redirect to list end

so in browser http://localhost/product/list?top=10 i will get the top 10 heaviest product i edit on of the product then it will bounce back to list?top=10 instead of list

the question is: how can i maintain the params[:top] across several methods in 1 controller or several controllers?

Thank you

Store in session variable