If you have infants in care when worked in centres that had these they were awesome and could 'stack' when not being used for 'smaller' infants - our infants rooms when have a few of these and than 1 table like above for the 'older' infants ... everywhere I worked by the time the children were 15 months we were transitioning them to sit in the above style because they would be moving up to the toddler room shortly and not have the highchair option there.

you can get these at a restaurant supply store