NBS Source


Suitable for installation in various wall types including stud and blockwork.


The GRS-DUO is designed to prevent air leakage at pipework penetrations behind a radiator that is plumbed with 10mm flexible plastic barrier pipework, commonly used for central heating systems in modern buildings.

Along with limiting air leakage through the penetration and producing an attractive finish to the detail, the product also acts as a guide for the pipework as it exits from behind the wall and transitions below the radiator to the valve points at the outer corners, eliminating the risk of kinks and chafing along the exposed run of pipe.

The patent-pending twin plate design allows for a robust mounting point for the pipework at the first fix plumbing phase, with the subsequent penetration through the plasterboard behind the radiator then covered and sealed against air leakage during the course of the second fix.

The versatility of the system allows it to be installed in a wide range of details and with both blockwork and stud wall constructions. The single central fixing of the sealing cover plate can also be secured directly to the rear mount plate rather than into the surrounding plasterboard, which removes the need for plasterboard fixings near to the cut edge of the plasterboard pipework opening. The mount plate offers a series of fixing locations to allow the system to be fitted securely with a variety of plasterboard and radiator offsets.

Features and benefits:

  • Twin plate system to maximise the benefits for first and second fix installations.
  • First fix mount plate anchors the pipework at the correct point of exit from the wall.
  • Guide channels help to curve the pipework towards the valves to prevent kinking.
  • Second fix cover plate attached with a single screw, no plasterboard fixings required.
  • Multiple pilot hole locations between the two plates allows for various installation offsets.
  • Flexible grommets seal around the pipework while allowing for directional adjustability.

General information





Cover plate (mount plate is black).


Mount plate: Polypropylene.

Cover plate: Polypropylene and TPE.



Thermoplastic elastomer.


135 x 128 x 22 mm


Pr_65_52_61_96 Wall collarsPrimary


P31/710 Sealing

P31/40 Sealing around services

Specification data - Wall collars Enhanced data


Polypropylene mount plate and cover plate, TPE cover seal.


Mount plate: 65 x 100 x 41 mm; Cover plate: 135 x 128 x 22 mm.

Environmental information

Country of product manufacture

United Kingdom


Manthorpe GRS-DUO - Housebuilder Launch Handout

Manthorpe GRS-DUO - Housebuilder Launch Handout