Solis Knock Box 
 
This knockbox is made from very durable black plastic with a solid hardwood knock bar that is hard enough to absorb the knock yet soft not to harm the portafilter basket. Included anti-slip silicon feet that prevent the box from moving and scratching the counter top when knocking the ground coffee.
The hardwood bar can be covered with short rubber hose (can be found in your local hardware store or automotive parts) if you wish the knocking to be quieter.
  
Simple and extremely durable, Swiss made, easy to clean.
Now you can have a clean kitchen and a semi automatic espresso machine.
 
 Dimensions: 3.5"H x 4.5"W x 9"D