A corner block adjustment mechanism for use with a container, said corner block adjustment mechanism comprising: a base adapted to be coupled to the container, said base including a central axis, a chamber, and a distal end having an opening in communication with said chamber; a stem having a proximal end and a distal end, said stem extending through said opening in said base and into said chamber of said base; a corner block coupled to said distal end of said stem; a cam rotationally coupled to said base and to said stem, said cam being selectively rotable about a first axis of said cam with respect to said base and said stem, said cam being selectively rotable between a first position wherein said corner block is located in an extended position with respect to said base and a second position wherein said corner block is located in a retracted position with respect to said base, said cam adapted to move said corner block generally parallel to said central axis of said base between said extended position and said retracted position of said corner block as said cam is moved between said first position and said second position of said cam; characterised in that it comprises: a locking mechanism adapted to releasably lock said cam in said first position and to releasably lock said cam in said second position, wherein said locking mechanism includes a locking member adapted to releasably engage said cam, said locking member being selectively movable between: a) a locked position wherein said locking mechanism is adapted to prevent rotation of said cam about said first axis and b) an unlocked position wherein said locking member allows rotation of said cam about said first axis. a base adapted to be coupled to the container, said base including a central axis, a chamber, and a distal end having an opening in communication with said chamber; a stem having a proximal end and a distal end, said stem extending through said opening in said base and into said chamber of said base; a corner block coupled to said distal end of said stem; a cam rotationally coupled to said base and to said stem, said cam being selectively rotable about a first axis of said cam with respect to said base and said stem, said cam being selectively rotable between a first position wherein said corner block is located in an extended position with respect to said base and a second position wherein said corner block is located in a retracted position with respect to said base, said cam adapted to move said corner block generally parallel to said central axis of said base between said extended position and said retracted position of said corner block as said cam is moved between said first position and said second position of said cam; characterised in that it comprises: a locking mechanism adapted to releasably lock said cam in said first position and to releasably lock said cam in said second position, wherein said locking mechanism includes a locking member adapted to releasably engage said cam, said locking member being selectively movable between: a) a locked position wherein said locking mechanism is adapted to prevent rotation of said cam about said first axis and b) an unlocked position wherein said locking member allows rotation of said cam about said first axis. a locking mechanism adapted to releasably lock said cam in said first position and to releasably lock said cam in said second position, wherein said locking mechanism includes a locking member adapted to releasably engage said cam, said locking member being selectively movable between: a) a locked position wherein said locking mechanism is adapted to prevent rotation of said cam about said first axis and b) an unlocked position wherein said locking member allows rotation of said cam about said first axis. a) a locked position wherein said locking mechanism is adapted to prevent rotation of said cam about said first axis and b) an unlocked position wherein said locking member allows rotation of said cam about said first axis.