I took a small cartridge for the device and added ordinary faucet water without using any of my actual stuff then got rid of the empty space before putting it in place. I turned the dial to fifteen and skipped attaching any pen needle instead I grabbed an ordinary insulin syringe poked it into the cartridge and triggered the plunger on the device. The syringe ended up with exactly fifteen units when the mechanism worked properly but other amounts like ten or twelve or twenty five told me the correction needed. Later on I tried some different automatic injectors and they turned out really nice.
Like many others, I began with one peptide and soon added two more to my routine. As someone who pins in the morning, I once mistakenly injected into my rear thinking of another substance due to a moment of distraction, instead of my abdomen. It didn't affect how well it worked but made me worry about future dosing errors. So I got into using pens. After looking into it a lot and seeing videos recommended here, I purchased two of the updated models for my copper peptide and NAD+, and I won't go back. Thanks to the long-time members for building this useful space where beginners can learn and feel okay getting and trying new tools to simplify mixing, cleaning, and loading vials. Pens look daunting at first but step by step it's straightforward, and I'd suggest trying them if interested. I still stick with needles for the first one, so now I associate needles only with abdominal injections. The pens are for the rear.