A bit of a specialised item here. A double rail chair for use with bar rail, for making check rails.
My 7 1/4g garden railway is built with 20mm by 10mm flat bar. I use moulded plastic chairs from PNP Railways here in the UK. These are excellent, however PNP only make single slot chairs, not double. I needed check rails on two curves and some points. I therefore designed these to match the PNP chairs. One has a 10mm gap between rails, and the other has an 8mm gap. I designed them for use with No.4 stainless chipboard screws. One slot is higher than the other, and this is for the inner rail
I printed mine in PLA with 25% infill. So far I have had no failures, and one part of the track runs across my gravel driveway. I run over this every day with my 4x4 pickup!
I use them every other sleeper on the curves.