Abstract: An equestrian vest for a horseman has a plurality of selectively useable shock absorbing and impact resistant panels. Each panel comprises a grid or network of discrete pockets, each containing a shock absorbing or impact resistant element, respectively. Grid lines of the panels are aligned and oriented in overlapping fashion when the panels are assembled in a vest and the vest us this very flexible and form fitting, while offering significant user protection.

Abstract: A fire retarding heating and cooling duct to impede the progress of fires in buildings and houses. The fire retarding duct is comprised of a duct core covered with a heat meltable plastic material that will melt at temperatures in the range of 180.degree. F. and above. The duct core is preferably constructed in short sections of about six feet for connection between heating and cooling, and building inlet and outlet plenums. The heat meltable plastic duct covering melts almost immediately when a building fire enters a plenum preventing the spread of a fire throughout the duct system.

Abstract: A completely sealed knock-down collar for joining heating and cooling ducts to plenums. The knock-down collar is formed from an elongate sheet metal strip punched with a plurality of tabs along one edge, a plurality of diagonal slits spaced from the tabs, a target on one end and a slot on the other. The sheet metal strip is rolled into a tubular shape with diagonal slits forming a herringbone mounting flange and the tongue fitting the slot to lock the strip in the tubular shape. A non-drying sealer is provided beneath the herringbone mounting flange and along one end to seal the collar when mounted in a plenum.