Hartridge Test Equipment technical services bulletin No. 175/5 for the Mk.3 Smokemeter. Bulletin replaces 'bulletins 174, 174/1, 174/2, 174/3 & 174/4 which should be destroyed'. Leaflet: 'Hartridge Test Equipment Bulletin No. 175/5'
Operating and maintenance manual for Hartridge Test Equipment Mk3 Smokemeter & Mobile Power Units (Types 'SB1' and 'SM1'). Manual: 'Operating and Maintenance of Mk3 Smokemeter & Mobile Power Units Types 'SB1' and 'SM1''
