Box of 20 Round Power Liner Cartridge Needles from Emalla
Diameter 0.4mm, long taper 5.5mm
Features:

Shining blue tip is easy to clean
Accurate slot design fits 99% of pen machines
The back blister paper is easy to open
Cartridge system avoids ink back flowing
Membrane inside is not easy to pull apart
Membrane with 4 thickened bars, more durable
Soft and strong flexible membrane material
All with CE certificate, sterilised by EO GAS