For childsafetywhen doorways are wide, use these optional T-Bar supports for Cardinal Gates Stairway Special Model SF-SS-30 , Duragate Model SF-MG-15 and optional Extensions, BX-1 and BX-2. These safety gate extension bases add stability to child gates and pet gates. For wide doorways or hallways, use one T-bar for every two 21.75" safety gate extensions (BX-2 WHITE) with Stairway Special Gate and MG 15.