Spare "glass" for an iStick Pico tank. This needs a tight fit to seal properly. So your first print will most likely not fit perfect.Don`t force it too hard, or you might damage the seal.
In simplify 3D, click on "Edit Process Settings" go to the tab "Other" and on the bottom left you will find "Horizontal size comensation" Set it to a negative value if your print is too tight. If you are using a 0.4mm nozzle, you will most likely need something around -0,20mm (Half the nozzle size) Play around with the values untill you get a perfect fit.
I am sure there is a similar setting in cura, maybe someone can post it in the settings.
I printed mine using PETG and it seems to be working good.