Viking Quick Response Flush Pendent Sprinkler VK478 is a small high-sensitivity  fusible element sprinkler designed for installation on concealed pipe systems where  the appearance of a smooth ceiling is desired. The two-piece design of the sprinkler and ceiling ring allows installation and testing of the sprinkler prior to ceiling installation. The ceiling ring allows for up to 5/8” (16 mm) of vertical adjustment and can be removed and re-installed, allowing access above removable ceiling panels without shutting down the sprinkler system and removing the sprinkler.