The Standard, Premium and Gold ranges are all 3 mL borosilicate glass pen cartridges supplied in 10-packs. The differences are in how they are processed, whether the plunger is installed or supplied separately, and the documentation available for the batch.
Standard, Premium and Gold at a glance
| Range | Plunger format | Specified processing | Documentation |
|---|---|---|---|
| Standard | Factory-installed plunger | Single washed, siliconised and steam sterilised after assembly | Independent Verifi sample report |
| Premium | Separate washed plunger in each sealed pouch | Washed, siliconised, terminally EO sterilised after packaging and aerated | Independent Verifi sample report |
| Gold | Separate washed plunger in each sealed pouch | Three WFI wash-and-blow cycles, siliconisation, depyrogenation at 280°C, terminal EO sterilisation and aeration | Manufacturer-issued report for batch KK251001 |
Independent testing: Standard and Premium both passed
We commissioned Verifi Labs to test Standard and Premium cartridge samples. Both reports, issued on 23 September 2026, recorded no growth detected for total aerobic microbial count (TAMC) and total yeast and mould count (TYMC). Both samples were marked Pass.
The reported method is TAMC / TYMC Microbial Detection using PetriFilm Plates. This is microbial enumeration testing, not a full sterility test. Results apply to the submitted samples; the batch / lot field on both reports is listed as Not set.
| Range | Sample ID | TAMC | TYMC | Overall result |
|---|---|---|---|---|
| Standard | 7MSB | No growth detected; Pass | No growth detected; Pass | Pass |
| Premium | 6HBG | No growth detected; Pass | No growth detected; Pass | Pass |
Why do Premium and Gold have separate plungers?
For Premium and Gold, keeping the washed plunger separate leaves its surfaces exposed during terminal EO sterilisation. Each plunger is supplied inside the same sealed pouch as its cartridge. Standard arrives with the plunger factory installed before steam sterilisation.
Watch: how to fit the plunger
This short video shows how to fit the plunger in Premium and Gold cartridges while both parts remain inside the sealed pouch.
IMPORTANT INSTRUCTION:
While the plunger and cartridge are still inside the sterilised pouch, use your thumbs to position the plunger in the open end of the cartridge, then press it firmly into place.
Washing, sterilisation and depyrogenation: what is specified?
Standard and Premium share a washed and siliconised cartridge specification but use different assembly and sterilisation formats. Gold adds documented WFI washing and 280°C depyrogenation before terminal EO sterilisation. These are manufacturing distinctions, not a claim that one range is clinically superior.
Read the Standard, Premium and HDRSMTMED sample test comparisonWhich Grey Depot pens fit these cartridges?
All three Grey Depot reusable pens fit every listed Standard, Premium and Gold 3 mL glass cartridge: the Reusable Injection Pen (60 Units), Slim Reusable Injection Pen (80 Units), and Gansulin Reusable Injection Pen (60 Units) with Case.
Read the reusable pen buyer guide See what the cartridge caddy holdsWhat does the Gold batch report cover?
Gold has a separate manufacturer-issued report for batch KK251001, dated 20 August 2026. It records sterility as complies, bacterial endotoxins at <0.125 EU/mL (complies), and ethylene oxide residue as not detected (complies). These are the manufacturer's findings for that batch, not independent laboratory testing or results for Standard, Premium or future Gold batches.
Gold: manufacturer inspection report, batch KK251001 (PDF) Compare current cartridge options and documentation