Single Refillable Pen

This single refillable pen comes complete with a discreet carrying case for convenient use on the go. Please note that tips and cartridges are not included. To use, fill your product vial with water, withdraw 1ml of solution and inject into the pen cartridge via its small opening, then withdraw 1ml of air from the cartridge and repeat until full. Easily assemble by installing the cartridge, attaching the needle, pushing out any air, then setting to the desired units (100 units = 1ml). Replace the 4mm tip after each use, and always use a new cartridge for every finished vial.