Use these connectors to stack one of our Floating Trays Mini Ink units/base on top of another. 4 pieces Install at the four upper corners of the lower base. Fit a second base on top of lower base. Do not stack more than two bases. Matte ivory finish Cannot be used in conjunction with Side to Side Connectors. We recommend placing our Floating Trays Mini Ink units on a desk/table against a wall. We advise AGAINST stacking our units unless you have these stacking connectors. Even with 4 stacking connectors installed on one unit, we advise AGAINST stacking more than two of our Floating Trays Mini Ink units. DO NOT STACK MORE THAN TWO. Stack at your own risk. We are not responsible for any damage for units that fall off surfaces because they are not flush against a wall. NO REFUNDS OR RETURNS FOR ANY UNITS THAT FALL OFF A SURFACE. Please ensure units are flush against a wall.