The closers in this section are for specific niche markets, from the high-end residential Duo-Chek® to the high-security SEC27-180 closers. No two have the same features. Designed for interior doors that have lower usage (10-500 cycles a day). They are perfect for high-end residential or interior office spaces. They are unique in performance and design. With case depths of 3 inches or less, they are ideal for thin slab applications for wood floor installations.The Duo-Chek® is for high-end residential applications such as the double-acting door going from the kitchen to the dining room. The weight of the door is supported at bottom.