Mongrel 561 Side Zip Safety Boots - STONE
£139.99
£139.99
Details
Overview
The Australian-made Mongrel 561 High Leg ZipSider Safety Boot is Mongrel’s toughest boot, built for the hardest, hottest jobs in the UK. A higher-cut side-zip work boot with a premium full-grain leather upper, it’s made to take punishment. Its standout feature is a genuine Vibram® outsole that withstands heat up to 300°C and resists oil and acid — which is why it’s a confident choice for boiler makers, miners, grinders, metalworkers and road workers who need protection from heat.
A 200J steel toe cap and moulded PU scuff cap handle protection, a Silicone AbrasionGuard shields critical seams and adds impact protection, and a YKK side zip is protected by a full-length leather ZipGuard. Inside, the OrthoTec® Poron® footbed and AirZone® Comfort System deliver all-day comfort with shock absorption and anatomical arch support, while a Dri-Freeze® lining dissipates heat and manages moisture. Built to last with Nomex® stitching and a padded tongue and collar.
Take a closer look in the Mongrel 561 introduction video, or download the full Mongrel 561 spec sheet (PDF).
Want a lighter, lower-cut everyday boot instead? See the Mongrel 461 Side Zip with Scuff Cap.
Key features & specifications
- Safety rating: EN ISO 20345:2022 — S1 FO SC SR (200J steel toe, antistatic, energy-absorbing heel, fuel/oil-resistant outsole, scuff cap, top-grade slip resistance)
- Certified: AS 2210.3:2019, ISO 20345:2011 (MOD), ASTM F2413
- Toe protection: 200J steel toe cap with moulded PU scuff cap
- Style: High-leg (higher-cut) side-zip work boot with YKK zip & full-length leather ZipGuard
- Upper: Premium full-grain leather
- Outsole: Genuine Vibram®, heat resistant to 300°C, oil & acid resistant, SRC slip rating
- Seam protection: Silicone AbrasionGuard
- Comfort: AirZone® Comfort System + premium PU cushion midsole
- Footbed: OrthoTec® Poron® with anatomical arch support
- Lining: Dri-Freeze® heat-dissipating moisture management
- Stitching: Nomex®
- Antistatic: Yes
- Made in: Australia
- Sizes: UK 5–13 (including 6.5–10.5 half sizes)
Who it’s for
The 561 is built for heavy-duty and high-heat trades: boiler makers, welders, fabricators, metal workers, grinders, foundry and engineering work, mining and road work. The 300°C Vibram® sole and higher-cut design make it the pick when heat and durability matter most. For lighter, everyday site work on dry ground, the lower-cut 461 may suit better (see FAQs).
Sizing & fit
Mongrel boots generally fit true to size in UK sizing, with half sizes available through the mid-range for a precise fit. If you’re between sizes or wear thick work socks, we’d suggest going up to the next half size. Not sure? Get in touch and we’ll help, and we offer free exchanges if the fit isn’t right.
Why buy from BIG Boots UK?
We’re a small, family-run business that lives and breathes Australian work boots. Originally from Australia ourselves, we know these brands inside out and only stock boots we’d wear on our own feet. Every pair is genuine, fully warranted, and backed by people who actually use them on the tools.
FAQs
What’s the difference between the Mongrel 561 and 461?
Both are Australian-made steel-toe side-zip safety boots. The 561 is higher-cut and heavier-duty, with a Vibram® outsole rated to 300°C — built for heat and metalwork. The 461 is lower-cut, lighter and a little cheaper, with a TPU outsole — better for general everyday site work. Choose the 561 for high-heat trades, the 461 for all-round comfort.
How heat resistant is the 561?
The genuine Vibram® outsole is rated to 300°C and resists oil and acid, which is why the 561 is popular with boiler makers, welders, grinders and foundry workers. As with any PPE, always match your footwear to your specific workplace risk assessment.
What does the S1 safety rating mean?
Under EN ISO 20345, S1 means the boot has a 200J toe cap, antistatic protection, an energy-absorbing heel and a fuel/oil-resistant outsole. The 561 adds a scuff cap (SC) and top-grade SRC slip resistance. Note S1 boots are not water-resistant and don’t include a penetration-resistant midsole — if you need those, choose an S3-rated boot.
Do the boots stay secure with a side zip?
Yes. Lace the boot once for your ideal fit, then use the heavy-duty YKK side zip — protected by a full-length leather ZipGuard — to get on and off quickly each day. No re-lacing, and nothing to snag around machinery.
Are Mongrel boots true to size?
Mongrel boots generally fit true to size in UK sizing, with half sizes through the mid-range. If you’re between sizes or wear thick socks, size up to the next half size. We offer free exchanges if the fit isn’t right.
Where are Mongrel boots made?
Mongrel Boots are proudly made in Australia and have been since 1930, using premium full-grain leather and quality components like the Vibram® outsole on the 561.
Do you offer next day delivery?
Yes. We offer fast UK delivery with express and next-day options at checkout — see our delivery page for the latest options and cut-off times.
Sizing Recommendations
Shipping Details
Next Day delivery for express orders placed before 2pm (Business Days Only) Free for orders over £110 or boots over £110
Standard Delivery:
Free Postage for orders over £60 - Royal Mail Tracked 48 with text & e-mail updates
Normally arrives in 2-3 business days
Orders under £60 - Royal Mail 48 Tracked - £2.99
Normally arrives in 2-3 business days
Royal Mail 24 or Parcel Force - £6.50
Next day delivery for orders placed before 2pm!
(Business Days Only) - Select at Checkout
Text and e-mail updates included
All our orders are tracked however if you have any concerns, please feel free to contact us.
Overboots are sent with Royal Mail as a large letter so may not have tracking.
**Please note
We will always try to make sure your orders arrive as soon as possible however please understand once it's with the courier, it's out of our hands.
Please contact us if you have any questions
ryan@bigboots.co.uk
Creating quality boots with a straightforward objective - to establish ourselves as the finest work boot manufacturers in Australia.
Mongrel Boots, an Australian footwear company, has been skillfully crafting boots since the year 1930. Our family's rich tradition of boot making, ingrained in our lineage, has been faithfully handed down through the ages right from the outset.
BUNDLE DEAL
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FAQs
Do you offer next day delivery?
Yes we do, for £6.50 and if you order before 2pm, you’re order should arrive the next day with Royal Mail or Parcel force.
Boot orders over £110 get free next day delivery. Steel Blue Boots and Mongrel Boots get free express postage.
How do I return or exchange my items?
We recommend for any exchanges, you purchase the size you're after and then return your current pair for a refund. This saves time waiting for your new item to arrive.
We know buying footwear and workwear online can be difficult, so we try to make returns as easy as possible. You arrange the return postage back to us, which is how we keep our express delivery free.
Please click here to start the process.
Do you ship to Europe and Ireland?
Unfortunately not, we do ship to Northern Ireland however due to brexit and the complications with shipping and then duties costs, we find it better for customers to try and find a local supplier as it will save you money on duties.
Northern Ireland customers do not have to pay duties as you’re part of the United Kingdom and postage is the same as the mainland.
My boots are faulty within the 6 month warranty period, what do I need to do to submit a claim?
Please click on the link below and follow the instructions. If your boots are just outside 6 months, please contact us directly to discuss options - ryan@bigboots.co.uk or 0330 043 0873
https://www.bigboots.co.uk/pages/steel-blue-warranty-details
Do you have a physical store?
Unfortunately we don't at the moment. We're in the process of looking for a new showroom and once that becomes available, we'll let you know.