SnoopFab 3d printed captive spark plug stand is designed around the ngk BR6 spark plug utilizing orings to hold the body of the plug so they stay in the block and not scattered all over the pit. Rubber tabs on the bottom ensure the block stays where you place it without it sliding or scratching paint. Comes with 8 standard 3/8" ID 70a durometer orings installed but they can be swapped out with softer/harder durometer orings to fit a wide range of plugs. Available in Ford or Chevy cylinder patterns