This model was inspired by the IKEA Skadis Holder for Gridfinity Case. 

I designed this holder to hold a 5x4 Gridfinity Storage Box by Pred (https://www.printables.com/model/543553-gridfinity-storage-box-by-pred-now-parametric) and can be mounted on an IKEA Skadis pegboard.

I have printed it in PETG and there the tolerances work perfectly, I cannot guarantee that the tolerances will be right with other materials.