What pen do I order

*bump*

Do you really mean 100ml cartidges? Sounds very large for cartridges - most are 3ml. Also, do you mean Lantus insulin?
Generally, insulin manufacturers are helpful with this sort of enquiry, so you could try contacting them by phone or email or webpage.

Hi Nicky

I also enquire did you mean Lantus (Insulin Glargine) 3ml cartridges (300units)?

If yes the cartridges will fit the following pens:

Autopen 24 (manufacturer is Owen Mumford) available in 2 sizes of 1 unit increment 1-21 Units (Pen is Green) or 2-42 units (Pen is Blue)
OptiPen Pro (manufacturer is Sanofi-Aventis) – pen is 1unit increment 1-60 units (Pen is Green or White in colour)

Both are available on prescription in the UK.

Txx