Inspired by the general structure of various coin sorters, this simple model was designed to keep my dilators from falling over on my nightstand. The four slots are sized to hold dilators with diameters of 1 1/8", 1 1/4", 1 3/8", and 1 1/2", with some extra tolerance so they slot in easily.

The design could probably benefit from some improvements, but it works well enough as-is.