Viking Standard and Quick Response Concealed Pendent Sprinkler VK4621 is a thermosensitive glass-bulb spray sprinkler designed for installation on concealed pipe systems where the appearance of a smooth ceiling is desired. The addition of a durable and lightweight installation wrench allows for installation with the protective cap in place, minimizing the chance of damage to the sprinkler during installation. Viking also offeres a cap removal tool to aid in finishing the job from the ground.