The standard EXPAND-O-LIZER BS (Bow Spring) range are hinged, non-welded bow-spring centralizers designed to centralize in less demanding wellbore applications where rotation is not a requirement. The hinge allows the centralizer to be fitted on larger bore casing where weld-on connectors do not allow for a slip-on unit to be installed.


  • API certified - engineered and tested to exceed API 10 D
  • Low insertion and running forces
  • High restoring forces
  • Suitable for passing through wellbore/cased hole restrictions
  • High quality spring steel grade


  • Centralizer placement / T&D analysis available
  • Dedicated engineering support team
  • Size range 2-7/8” - 30”
  • EXPAND-O-LIZER BS range  
    • Conventional Bow Spring
    • Semi Rigid Bow Spring
    • Positive Bow Spring

For specifications, application solutions, and EXPAND-O-LIZER BS availability, please contact your local Downhole Products representative.