Trick to disassemble the Lamy Z28 converter: put it in the fridge for a few minutes, then the metal ring can be pulled off easily with a rubber grip : r/fountainpens
LAMY] Converter (LZ 28) – Baum-kuchen
Lamy Safari Z24 Converter for safari and al-star pens. Local source - Pen Boutique Ltd
Lamy Fountain Pen Converters Explained: Z24 vs Z28, Z26 vs Z27, Z27 vs Z28 - YouTube