Pen storage system - units side by side

Pen storage system to allow for 2 units locked side by sideHolds 36 pens per unit depending on pens (12 x 3 rows)Base (wedge), to tilt the unit backwards to help pens stay in unit.Top unit has flat top Print as many middle units as you need.The units slide and lock together to produce a tower.Units are 270w x 39h x 128d