K&M 18880 Table Style Keyboard Stand (Black)

It folds flat, with some space between the two sides taken due to bolt heads butting, but less than 1/2 . Altogether I'd guess about 4 thick or less. Height depends on how high you set the low tier, which you don't want to adjust at the gig. Folds flat well with tiers left on and just squashed down if necessary (I didn't bother.)