A replacement rubber bar for the the 1st series Classic Knockbox or Drop Knockbox.   You need to reuse the existing stainless steel rod and the 2 end nuts.

Classic Knockbox: http://www.cafelatstore.com/products/classic-knockbox

Drop Knockbox: http://www.cafelatstore.com/products/drop-knockbox

This bar does not fit the Stainless Steel Knockbox with the removable bar.

Material: NBR Rubber