Quartz thimble 20310 suits SLT40 and SLT75 UV systems.
IBC Defender 35, 65 and Defender 100 systems UV-VSL900L, UViFLO 4000
These thimbles have one open end and one closed end.
895mm long x 24.5mm OD x 21.5 ID
The o-ring to suit these thimbles are the 31001 UV o-ring