Hexatronic MPB30609/12 (Millennium part 673611) is a soft temporary end cap for 12 mm OD microduct, part of the Hexatronic Duct Seal family. Crews slip it over open duct ends between construction phases to keep water, silt and rodents out of the bore while the pathway waits for cable. Duct contaminated during the gap between placement and jetting is the usual cause of failed blowing shots and unplanned excavation. Because the cap is soft and pushes on by hand, it installs and strips off in seconds with no tools, making it practical for high duct counts.