The file 'Hollow (18 Mm) Bolt And Nut – For Water Level Gauge 3D Printer Model' is (stl) file type, size is 395.6KB.
This is a hollow nut/bolt combination with a hole of 18 mm diameter. This fits those cheap water level gauges.
Hollow_Bolt_18mm.stl | 413.5KB | |
Hollow_Nut_18mm.stl | 458.7KB |