Increasing MI-FLEX Adaptor - Ø 125-Ø 150
At a Glance
- Premium 316L stainless steel construction
- Robust 0.6mm thickness for enhanced durability
- Heat resistance rated up to 600°C (T600)
- Seamless connection between single wall flue and MI-FLEX liner
- Compliant with Building Regulations Document J
- Versatile for wood, oil, gas, and smokeless coal appliances

We Won't Be Beaten On Price
At National Flues, we continuously monitor competitor prices. This ensures that we consistently offer you the best deals on all our products. Here’s how we keep your costs low:
- Daily Price Matching: Our team adjusts prices to ensure we stay competitive.
- Bulk Purchasing Power: We sell a lot, so we can negotiate better rates with suppliers, passing the savings directly to you.
- Operational Efficiency: We have streamlined processes to reduce overhead.
Price Match Guarantee: If you find the same product cheaper within 48 hours, we’ll match it and refund the difference.
Free Delivery Over £100: Orders over £100 are free delivery (call us if delivery is required outside the mainland UK).
“I saved 20% on my purchase compared to other retailers. Exceptional service!” – Jane D.
Have Questions?
Phone: 01670 206999
Email: [email protected]
- Info
- Specs
- Install
- FAQs
The Increasing MI-FLEX Adaptor - Ø 125-Ø 150 is a high-quality 0.6mm 316 stainless steel accessory designed for seamless transition and connection between a single wall connecting flue system and an MI-FLEX flexible flue liner. Constructed to withstand temperatures up to 600°C (T600 designation), it is suitable for use with wood (less than 20% moisture), smokeless coal, gas, and oil appliances. This adaptor is essential for forming a complete chimney system in compliance with Building Regulations Document J, requiring a fully enclosed masonry chimney.
Do not use non-masonry enclosures like timber or plasterboard. Ensuring a gas-tight seal at the bottom fixing, the connection should be secured within the masonry chimney, utilizing fire cement, ceramic rope or tape, or high-temperature sealant. Regular sweeping and maintenance by a competent person are vital, especially for solid fuel appliances.
Use only appropriate cleaning tools, avoiding chemical cleaners and mild steel tools. Recommended sweeping twice a year ensures the longevity and safety of your chimney system.
SKU: 20-125-MR
Technical Specifications | |
---|---|
Model | 20-125-MR |
Material | 316L Stainless Steel |
Thickness | 0.6mm |
Heat Rating | T600 (Up to 600u00b0C) |
Finish | Natural / Stainless Steel |
Compatible Fuels | Wood (with less than 20% moisture), Oil, Gas, Smokeless Coal |
Certifications | HETAS / CE |
System | MI-FLEX Accessories MF20 |
Installation Method | Secured within a masonry chimney using fire cement, ceramic rope or tape, or high-temperature sealant |
Delivery Information +
We work relentlessly to ensure you get your order fast. Estimated delivery for this product is Wednesday, April 2nd. If you need faster stove or fireplace delivery please give us a call. We can often reduce longer lead times if we pay the carrier £25 for express delivery. Visit our Shipping Information page for more information.
Warranty & Returns +
All our products come with warranties. Mi-Flex offers a lifetime guarantee. Returns for damaged items are covered by insurance; non-damaged returns incur return delivery costs.
Price Match Guarantee +
We will match any price like for like. If you find it cheaper within 48 hours, we'll refund the difference.
Compatible and other products that may be of interest...
National Flues Ltd Verdict
Our Increasing MI-FLEX Adaptor - Ø 125-Ø 150 is a top-notch fitment, designed with precision to connect single wall flue systems to MI-FLEX flexible flue liners. With nationwide delivery and reliability that retail and trade customers can trust, National Flues rarely gets beaten on price.
The Increasing MI-FLEX Adaptor - Ø 125-Ø 150 serves as a crucial component for connecting a single wall flue system to MI-FLEX flexible flue liners, ensuring a stable and compliant transition within masonry chimneys.
National Flues is a trusted supplier of high-quality fireplaces and flues across the UK, offering competitive prices and reliable delivery for both retail and trade customers.
