Flexsafe STR® 50L (multi-use DO/pH)

Flexsafe STR® 50L bag with 2 KPC ports for conventional multi-use pH and DO probes. Optimized for batch and fed-batch processes, delivered ready-to-use including all required gassing line filters.

Flexsafe STR® bags are to be used with Biostat STR® hardware.

Item No.: 
Qty. Graduation

Flexsafe® STR bags ensure excellent and reproducible growth behavior of the most sensitive production cell lines. The optimization of the resin formulation and the complete control of our raw materials, the extrusion process and the bag assembly guarantee a consistent lot-to-lot cell growth performance.

Flexsafe STR® standard design features

Flexsafe STR® STD bags feature two 3-blade segmented impellers ideal for mammalian cell cultures and a ring sparger for submerse gassing.

All gassing lines are equipped with OPTA® SFT sterile connectors for easy assembly of the included filter transfer sets. Substrate lines are made from weldable tubing for the secure connection of media, acid, base, antifoam agents and any other required feeds. Addition can be achieved either via the head space or through dip tubes.

A temperature sensor sleeve, a small volume sampling line with clave connector and a bottom drain harvest line complete each Flexsafe STR® STD bag.

Enhance safety and ease-of-use

Flexsafe STR® bags are delivered gamma irradiated and ready to use. All necessary gassing line filters are included with the delivery and can easily be installed using OPTA® SFT sterile connectors. Installation into Biostat STR® bagholders is easy and straightforward. To reduce process risks, all bags come with a redundant exhaust line. An optional single-use exhaust cooler can be used in addition to the standard filter heater to further mitigate the risk of filter blocking.

Do you need more?

For more advanced processes such as intensified perfusion processes, our range of configured-to-order (CTO) components offers unrivalled flexibility. Choose from advanced single-use PAT sensors such as BioPAT Viamass® for viable cell mass monitoring, add side ports for perfusion with ATF, or TFF systems and increase reliability through added sensor redundancy. Furthermore, tubing diameter on feed and gassing lines can be adjusted to fit process requirements. Connector options include OPTA® SFT sterile connectors, Aseptiquik®, and weldable tubing with MPC quick coupling connectors. Micro and Combi sparging enhance gas delivery and optional Rushton 6-blade impellers increase mixing performance. Reach out to your Sartorius representative to learn more on how Flexsafe STR® bags can be adapted to your process.

Aseptiquik® and MPC quick coupling connectors are products of Colder Products Company®. Aseptiquik® is a registered trademark of Colder Products Company®.


  • Application
    Cell Culture
  • Application Area
    • Cell culture
    • Cell therapies
    • mAB production
    • Recombinant protein production
    • Vaccine production
  • Scale
    • Pilot
    • Process

Connections (Physical)

  • Connectors
    Opta® SFT Connector
  • Sparger Type
    Ring Sparger


  • Sensors
    probe ports

Materials of Construction

  • Film Material

Product Information

  • Brand
    Flexsafe STR®
  • Impeller Type
    3 blade segmented


  • Working Volume
    12.5- 50L