flipper 86 extends perpendicular to plate 85 to enable entry of a stage leg 21 into the hook plate in its second position flipper 86 extends parallel to plate 85 and hence perpendicular to leg 21 which is thereby retained in hook plate 85 a special feature of the design of releasable means 83 is its adaptability for use when two brackets must be secured to the same stage leg as at leg 21a on the corner of the stage of fig2 this arrangement is seen in greater detail in fig9 and 10 fig9 shows a first bracket portion 80 releasably connected to a stage leg 21 its flipper 86 being at the horizontal or locking position a second bracket portion 180 for another module of the barrier is positioned to be connected to the same leg 21 at right angles to member 80 the flipper 186 of releasable means 183 is in its vertical or open position to receive leg 21 to secure releasable means 183 to the leg member 180 is lifted slightly approximately the thickness of the hook plate and moved towards leg 21 while at the same time moving it slightly to the side to bring the hook portion 188 of hook plate 185 around leg 21 fig1 shows the connection of releasable means 183 to leg 21 completed except that flipper 186 has not yet been pivoted to its horizontal or locking position in use a pair of brackets 36 have.