Southwark Metal 121SC18 Ductboard Snaplock Collar 18in

Product Description

The SOUTHWARK METAL 121SC18 is an 18-inch ductboard snaplock collar designed to create a secure, airtight connection point where flexible or rigid ductboard meets a plenum, air handler, or duct fitting. The snaplock design allows the collar to seat firmly into the ductboard face without requiring additional fasteners, speeding up installation on new construction and replacement jobs. HVAC installers use this collar to maintain airflow integrity and minimize leakage at duct transitions in forced-air systems.

The 121SC18 is suited for residential and light commercial HVAC ductwork systems where ductboard is the primary distribution material. It is most commonly installed at plenum takeoffs, air handler connections, and branch transitions on forced-air heating and cooling systems. The 18-inch diameter makes it appropriate for high-volume trunk lines or large branch runs.

Key Features

• 18-inch diameter snaplock collar for ductboard applications
• Snaplock seating mechanism eliminates the need for additional mechanical fasteners at the collar joint
• Designed to maintain airtight duct connections at transition points
• Compatible with standard ductboard construction methods used in residential and light commercial HVAC

Compatibility

Designed as an OEM-style replacement and new-construction fitting for 18-inch ductboard duct systems in residential and light commercial forced-air HVAC installations.

Installation Notes

Installation should be performed by a qualified HVAC technician. Power down the air handling unit and confirm the system is de-energized before working inside or adjacent to the air handler or plenum. Seat the collar fully into the ductboard face according to standard sheet metal and ductboard fabrication practices, and seal all joints with approved duct mastic or foil tape in accordance with local mechanical codes and SMACNA guidelines.

Technical Specifications

• Collar Diameter: 18 inches
• Type: Snaplock Collar
• Application: Ductboard HVAC Systems

Standard Information

• Brand: SOUTHWARK METAL
• Manufacturer Part Number: 121SC18