Abstract: An integrally formed plastic strip for use as a nailing fin for installing a window assembly in a building has a first stiff plastic member with nail holes through which the strip is attached to the supporting structure, a second narrower stiff plastic member for insertion into a kerf running along the outside of the window assembly for attaching the nailng fin to the window assembly, and a further narrow section of flexible plastic which hingedly connects together the stiff plastic sections so that the nailing fin can be attached to the window assembly and folded back to reduce space requirement during shipment of the window assembly.

Abstract: A plastic liner is attached to the jamb of a vertical sliding window and has a continuous "U" channel with the channel opening facing the window opening and a block member slidingly engaged in the channel adapted to be coupled to the window sash and to one end of an elongated coil spring located in the channel which is attached at its other end to the liner. Primary frictional braking force is provided by a wing member inside the channel pushing against the block member so it rubs against a wall of the channel. The block member rides over a "T" shaped rail in the channel and carries a set screw which can be reached through the channel opening to be threaded through the block member into contact with the top surface of the rail member for manually adjusting the frictional braking force on the block member.