# Underground Chamber Reducer – 450 to 350mm

This Underground Inspection Chamber Restrictor Ring (also known as a Reducer Ring) is designed to reduce the opening of 450mm inspection chambers to 350mm diameter. It is suitable for use with 450mm chamber bases, including B5494 and B5696, helping create a smaller access point while maintaining compatibility with the chamber system.

The ring is easy to install and can be fitted to any 450mm chamber base, regardless of the chamber depth or invert level. It is commonly used where the chamber depth exceeds 1 metre (1000mm), helping to provide a more practical and secure access size.

Ideal for underground drainage systems, this restrictor ring forms part of a complete inspection chamber setup, which may include the chamber base, risers, sealing rings, and a suitable cover and frame.

## Details

- **Price:** 31.62 GBP
- **Vendor:** BRETT MARTIN PLUMBING & DRAINAGE (B80B)
- **Type:** Underground Drainage
- **Tags:** Black, Building Materials, Chamber Reducer, Drainage, Local, Underground Drainage

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 31.62 GBP | In stock |

## Images

- Black plastic inspection chamber riser ring for drainage and building materials

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> Source: [Carvers Building Supplies](https://www.carvers.co.uk/products/underground-chamber-reducer-450mm-350mm-b6350)
> Updated: 2026-06-16