Abstract: A dry marker board including a sheet of material having a writing surface upon which felt tip, erasable ink markers may be used. Preferably, the writing sheet is a sheet of ceramic-on-steel material. A shelf support, preferably made of wood, is mounted on the bottom portion of the writing sheet by fasteners such as nails or screws. Polyurethane is injection molded around the peripheral edge of the writing sheet, encapsulating the peripheral edge and sides of the writing sheet and the shelf support to form a unitary frame with a shelf.

Abstract: A damper control apparatus for a fume hood which has a moveable sash, and wherein the damper control apparatus includes an axle assembly borne by the fume hood, a cable assembly borne by the sash and disposed in force transmitting relation relative to the axle assembly, and a damper borne by the fume hood and disposed in force receiving relation relative to the axle assembly and moveable along a path of travel into assorted operational positions which correlate with the position of the sash thereby regulating the amount of air withdrawn from the fume hood.

Abstract: A sash counterbalance device for a fume hood including a first cable having a first end and a second end, the first end being secured on the left side of a fume hood sash and wherein a first counterweight is secured on the second end of the first cable; a second cable having a first end and a second end, the first end of the second cable being secured on the right side of the sash, and wherein a second counterweight is secured on the second end of the second cable; and an axle which is mounted on the fume hood. The first and second cables are individually, separably, and concentrically wrapped about the axle such that movement of the sash causes a simultaneous movement of the axle by movement of the counterweights axle in a predetermined direction.

Abstract: A working surface including a substantially planar main body having a peripheral edge and first and second ends, the main body further having a male portion made integral with the first end and a female receiving station made integral with the second end, the male and female portions having complimentary shapes whereby individual working surfaces may be releasably joined together in, juxtaposed, end-to-end mating relationship to form a substantially continuous supporting surface.