The ag Ninja transition block is the safest way to allow your Ninjas to transition from one obstacle to the next on the Katana Frame. The block is designed to be the perfect height for the ninja to reach or step on to an obstacle. The 6ft block is meant to fit exactly between the uprights of the Katana Frame WITHOUT post pads. Frames with post pads should use our 5ft 10in long block. Our blocks are available in any standard vinyl color but our standard is black