JConcepts "Dirt-Tech" LP 1/10 Truck Closed Cell Insert. These high densisty inserts offer a great solution for low profile tires such as the JConcepts Smoothie 2 (JCO4049). Black in color, these updated inserts are designed in conjunction with insert guru’s Ryan Maifield, Spencer Rivkin, Jason Ruona, and Paul Wynn to bring a firmer touch and feel while still providing durability. The inside of the insert has horizontal channels cut in a 360 pattern to soak up the large impacts and help create forward bite and increase acceleration. Package includes two foam inserts.