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 5ft 10in block is meant to fit exactly between the uprights of the Katana Frame that HAVE post pads. Frames without post pads should use our 6ft long block. Our blocks are available in any standard vinyl color but our standard is black