Cardboard scratcher is a good way to make your cats take-off thier energy by scratching. Scratching is essential for all house cats because it lets them take out their frustations and also sometimes to express happiness. One of the major functionality is nail filing. Cat are very particular about filing their nails.
 
Side Length: 20 inches each side
 
Expert opinion: Once one side is fully used, reverse it to use the other fresh side. If it  becomes soggy during monsoon they dry it under the Sun & fast fan
 
Note : The price is high because it takes around 3/4th day to make this scratcher but it lasts longer than circle cardboard scratcher