Double-walled casings are used for stabilising boreholes in collapsible soil conditions. Casing and joints are designed for resisting the forces of BG-rigs or casing oscillators.

Main features of the casing system are:
- flush casing string (inside and outside), replaceable conical
  srew connections, variable length

Casing drive adapter transfer the torque from the rotary drive
onto the top of the casing string.

3 types of bolt connection systems are available: mechanical connection (bolts are fixed manually), semi-automatic with crank handle, automatic locking device

Casing shoes are important key elements on a casing string, especially when working in hard soil conditions or when constructing secant pile walls. Cutting rings on the cutting shoe are supplied either with weld-on teeth or with replaceable cutting teeth.

Special features:
- excellent cutting geometry with defined outside and inside
  free-cut area
- easy flow of soil material at the cutting edge / long lifetime
- maintenance and repair with easy means on site