LD-371 Steel Brass Surface Concealed Door Closer | Wholesale Supplier

The LD-371 steel and brass door closer collection is a versatile range of hydraulic door control devices engineered to deliver smooth, controlled, and automatic door closure across residential, commercial, and institutional environments. The collection encompasses both surface-mounted and concealed configurations, allowing architects and installers to select the optimal mechanism for each door’s functional and aesthetic requirements. Surface-mounted closers feature a robust cast iron or aluminum body paired with a brass or steel arm, providing visible, accessible, and easily adjustable performance ideal for retrofit installations and high-traffic commercial doorways. Concealed models embed the mechanism within the door frame or transom, delivering a clean, unobtrusive appearance that preserves architectural design intent while maintaining full hydraulic control capability. Each closer is manufactured under strict ISO 9001 quality controls and tested to EN 1154 performance standards.

At the core of every LD-371 door closer is a precision hydraulic oil mechanism that regulates the closing cycle through adjustable sweep and latch speed valves. The sweep speed controls the door’s travel through the main closing arc, while the latch speed governs the final 10 to 15 degrees of movement, ensuring the door closes securely and fully latches without slamming. The adjustable spring tension accommodates closing force ratings from EN size 2 to EN size 4, supporting maximum door weights from 60kg to 120kg and maximum door widths from 850mm to 1200mm. A built-in backcheck function protects the door, frame, and adjacent walls from damage by cushioning the door’s opening travel when forced open rapidly by wind, traffic, or abuse, making the LD-371 particularly valuable for exterior entry doors and high-traffic public openings. Body lengths range from 150mm to 200mm and arm lengths from 120mm to 180mm.

The LD-371 collection is offered in seven finishes to coordinate with surrounding door hardware and architectural schemes: polished brass, satin brass, antique brass, satin nickel, polished chrome, black, and silver. The brass and steel arm assemblies provide the structural strength needed for sustained commercial use, while the stainless steel spindle delivers corrosion-resistant linkage operation. These finish and configuration options make the collection suitable for an exceptionally broad range of applications, from classic residential interiors and hospitality guest rooms to demanding commercial office entries, retail storefronts, hospital corridors, and institutional fire-rated doors where reliable self-closure is mandated by building codes. The hydraulic dampening ensures quiet, slam-free operation that enhances occupant comfort and safety in every setting.

For wholesale buyers, hardware distributors, and OEM projects, the LD-371 door closer collection delivers exceptional value through competitive factory-direct pricing, extensive customization, and reliable global logistics. Mixed orders across surface and concealed configurations, closing force sizes, and finishes are fully supported, allowing buyers to consolidate their door closer sourcing through a single supplier. Customization options include OEM logo application, custom finishes, EN size 2-4 selection, surface or concealed configuration, and special arm styles including hold-open and parallel-arm variants. Each closer is packaged in an individual color box complete with the arm, mounting hardware, and installation instructions, with 10 to 20 pieces per carton. With a minimum order quantity of 200 pieces and a production lead time of 15 to 25 days, the LD-371 steel and brass surface and concealed door closer collection provides the quality, versatility, and supply reliability that professional buyers demand.