TDC - Transverse Duct Connector
Insted of cutting, assembling and installing a seperate flange onto the ductwork, the TDC flange is roll formed directly onto the duct. This provids a solid metal connection that reduces leakage which is why the TDC system is the best for minimum leakage application.
 Assembled on groun and some spans can be lifted at the same time, as manyspans as their lifting system can rise  
 Assembled and disassembled without suffering any damaged  
Flange with Sealant
G - clamp