Aluminium Coating Troughs (Scoop Coaters).

225mm (for use with screens with an internal measurement of 25cm) 
315mm (for use with screens with an internal measurement of 35cm) 
380mm (for use with screens with an internal measurement of 44cm) 
470mm (for use with screens with an internal measurement of 50cm) 

These troughs are designed to coat screens with Photo Emulsion. Trough is aluminium with removable plastic ends.