In addition to the round outlets, Unico also manufactures rectangular outlets. The rectangular outlets feature a narrow width slot that gives a better appearance in a sidewall installation. There are four (4) different types of slotted outlets. The type of outlet not covered by this bulletin is connected directly to the plenum and is described in Bulletin 20-58. This bulletin covers the three outlet types which are used in conjunction with the Sound Attenuator supply tubing. The Unico System straight slotted outlet (UPC-68) with its patent pending contour shape is designed for use where placement of the standard round outlet is not practical. The straight slotted outlets are particular useful where there is insufficient room for a round outlet at the desired termination point. A typical application for the straight slotted outlet would be placement in a cabinet soffit. The UPC-68 is made of plastic and is intended for residential use. Both the 90 deg and straight slotted outlets may also be used as ceiling outlets.