The surest way to fill your Tandem® t:slim insulin cartridge.

Take the guesswork out of finding your fillport.

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Instant accuracy for every fill.

CiertaTM provides help for:

Dexterity

Those who experience challenges with dexterity. 

Vision

Those who have experienced vision changes.

Consistency

 All who want to ensure a complete, accurate fill every time.

Simple & Smart!

Made from 100% biodegradable corn biomassees. You can be certain your Cierta is sturdy and secure without harming the environment.

Popular Questions

Got a question? We’re here to help.

  • What length needle does Cierta work with?

    Cierta is designed for the 3/8" long needle that ships with the Tandem t:slim X2 cartridge. It will work with 1/2" long needles, however, you may experience misalignment if the needle is not completely straight.

  • My needle won't align, what can I do?

    If your needle becomes bent during your insulin fill process it may not align with the fill port on the cartridge. Check to see that your needle is straight. If the needle continues to be misaligned, rotate the syringe 45 degrees and try again. 

  • How long will shipping take?

    All orders are shipped via USPS First Class Parcel Post. Most orders arrive within 5 days.

  • Will you ship internationally?

    International shipping is available. Add Cierta to your cart and proceed to checkout to view shipping rates for your location.

Order your Cierta today.

Free shipping on all orders in the US.