Abstract: A panel-holding strip or sash of extruded plastic composition which includes a pair of opposed channel-forming webs connected by an integral longitudinally coextensive, flexible bight or hinge web; the channel-forming webs being relatively movable in the manner of a book cover between a first open position in which the webs are disposed in angular relation to admit the edge portion of a panel or pane therebetween and a second, closed position in which the webs are frictionally interlocked in channel-forming configuration to hold the edge portion of a panel or pane therebetween; each of the channel-forming webs being formed on their opposing inner surfaces with a first set of relatively engageable and interlocking ribs to frictionally and releasably hold the webs in their closed, channel-defining position and a second set of relatively flexible ribs arranged to frictionally grip and seal the edge portion of a panel or pane positioned between the channel-forming webs of the strip or sash.