This is a wall mount for an air compressor filter (that removes moisture). It is over built as far as thickness, but it is solid enough for outdoor use and repeated handling (removing filter). The large hole could be re-sized to a radius of 29mm for a snug fit. Since I remove my filter instead of leaving it outside, I made it a little oversize. Also, keep in mind that any acrylic based moisture bowl will expand under pressure (don't make the hole too small).As with most prints, some cleanup of the holes may be required.