REDiBOX is a purpose-designed ‘left-in’ component for easy forming of recesses in concrete walls (precast or in situ). REDiBOX is configured to receive the sliding inner sections of TSS and RVK Telescopic Connectors cast into floors or landings. After cementitious grout fill, the connection is ‘unseen’ and fire resistant.

Invisible Connections’ range of permanent recess formers includes REDiBOX PRF-STD (standard version) and REDiBOX PRF-PIN (pinned version). REDiBOX standard version is used where the layout of connectors inherently tie floor or landing in position. REDiBOX pinned version enables robustness requirements to be met where the landing can only be fixed on two ends.

REDiBOX is manufactured from durable and recyclable high density polyethylene (HDPE) and sized to provide generous installation tolerance.

Features and benefits:

  • Recess fits within the depth of the floor so that the connection is hidden and clean architectural lines can be realised.
  • Manufactured from durable and recyclable HDPE contributes to environmental sustainability.
  • Once grouted the recess former is protected from fire so that fire resistance and reaction to fire requirements can be met.
  • Appropriate for installation across all concrete wall construction techniques (slip-form, jump-form or precast).
  • Different floor shapes and connector layouts can be accommodated and robustness compliance achieved.


  • Ribbed monocoque structure on back and sides provides strength and a substantial key to anchor it into the concrete wall.
  • Fully sealed unit ensures the recess will be clean once the face-plate is removed.
  • The rear of the detachable face-plate has an inset perimeter rib, which provides a close fit to the box and also maintains the shape of the recess former under concrete pressure.
  • The face-plate can be nailed to timber moulds or shutters. Alternatively, the integral lugs (two on four sides) provide fixing points to tie-wire the unit to the wall reinforcement (suitable for slip-forms).
  • Recyclable face-plate incorporates a central ‘soft-eye’ into which a hammer-claw can be inserted to pull and detach, revealing the clear recess.


  • REDiBOX PRF-STD: For use with TSS 41, TSS 101, TSS 102, RVK 101. When rotated 90 degrees may also be used with DTS 120 and DTS 150 connectors to support lightweight beam connections and Double Tee floors.
  • REDiBOX PRF-PIN: For use with TSS 81-30 and RVK 101-30 connectors.

Consult manufacturer for further details.

Standard product features


Durable and environmentally recyclable HDPE.


Product reference:


Used where layout of connectors inherently tie floor or landing in position.


Supplied with a white rebar tie-pin and 3D restraint U-bar with wire-tied crossbar. The white rebar tie-pin is conveniently housed inside the back of the recess former, easily accessed to position it through the hole in the telescopic connector and into the lower pocket of the recess former (thus enabling the axial tie). Alternatively, the entire unit can be secured into position using loose ‘trappings bars’ (not supplied) wired back to the main wall reinforcement.


- Vertical:

  • REDiBOX PRF-STD: ±35 mm.
  • REDiBOX PRF-PIN: +30/ -10 mm.

- Horizontal:

±40 mm (minimum).


A range of connectors are available for precast concrete stair landing connections, beam to beam connections, beam to column connections and connectors for miscellaneous applications are available. Consult manufacturer's literature and insert requirements for further information.

NBS Specification

NBS Create logo
This product is associated with the following NBS Create clause:
45-75-42/390 Carbon steel shear load connector

Product specification

An important note about specifying



Invisible Connections Ltd


+44 (0)1844 266000

Product reference

Standard version, 180 x 120 x 104 mm (internal, w x h x d).
Pinned version, 180 x 230 x 120 mm (internal, w x h x d).


[Foam rod]
[Levelling shims]

Manufacturer details

Unit 6 Thame Forty,
Jane Morbey Road,
Oxfordshire, OX9 3RR
Tel +44 (0)1844 266000
Fax +44 (0)1844 390167
NBS Plus