Euro cylinder measuring guide showing how to measure side A and side B from the central fixing screw to determine the correct cylinder size for your door

Not sure which size cylinder you need?

Euro cylinders are measured in two halves, separated by the central fixing screw. Take both measurements from your existing cylinder before ordering, and match them to the size listed above.

A — Internal side
Measure from the centre of the fixing screw to the outer edge of the cylinder on the side that faces inside your home. Common sizes are 30mm, 35mm, 40mm, 45mm, or 50mm.

B — External side
Measure from the centre of the fixing screw to the outer edge of the cylinder on the side that faces outside your home. Common sizes are 30mm, 35mm, 40mm, or 45mm.

Cylinders are typically described as A/B — for example, a 35/45 cylinder has 35mm on the internal side and 45mm on the external side. Get both measurements right and the cylinder will fit your door perfectly.

Still unsure? Send a photo of your existing cylinder to info@homesecureshop.co.uk and we'll match it for you — or call 0151 521 8089 to speak to our team.

Full measuring guide
Product overview

Top-rated security outside. Instant exit inside. The APECS AP Thumbturn pairs the two highest security ratings a euro cylinder can earn — the BSI 3-Star Kitemark (TS007) and Sold Secure Diamond — with a thumbturn on the inside, so you can lock and unlock your door from indoors without a key. No hunting for keys in an emergency, and nobody locked in because the key's gone upstairs — ideal for family homes, older residents and rental properties.

Outside, it defends like the rest of the AP range: anti-snap, anti-drill, anti-pick, anti-bump and anti-plug-extraction, with no add-on handles or guards needed. If the cylinder is attacked, a sacrificial point breaks away and a patented interlocking cam locks down the internals — and the dedicated release button on the thumbturn means you can still open the door from inside and exit safely, even after a snap attack.

  • Dual accredited — BSI 3-Star Kitemark (KM621947) and Sold Secure Diamond (CLME08161454), tested to TS007:2014 and EN1303:2015
  • Attack-resistant throughout — hardened carbon steel and brass construction, dimple/slider hybrid key, over 180,000 key combinations
  • £2,500 break-in guarantee — if a snapping attack on this cylinder ever succeeds, APECS pays up to £2,500 towards uninsured losses
  • 3 high-security keys included — copies cut to code only, so your keys stay under your control
  • Brushed Satin Nickel or Brushed Brass, sizes from 70mm to 110mm including offsets
  • Guaranteed for 10 years (5-year snap-secure guarantee)

A straight swap for your existing euro cylinder — no drilling and no door modifications. Measure both sides of your current cylinder to the centre screw before ordering.

Delivery & Returns

How much is delivery?

UK Mainland Delivery is £2.99 on all items no matter how many you order!

Northern Ireland, Scottish Highlands, Channel Islands £6.00.

We do not offer International Delivery (Ireland, France, Spain etc).

When will my order be dispatched?

Orders before 2pm (Monday to Friday) are usually dispatched same day but may take up to 24 hours.

When will I receive my item?

We ship on 2 working day courier. Fully Tracked. Tracking will be emailed on dispatch.

Special order items such as keyed alike locks will take longer to dispatch. Please refer to product description for lead times.

I haven't received my item?

Please email us your name, order number and date of purchase.

We prefer email as it allows us time to research and respond.

Returns Information

We operate a 30 day refunds and return policy.

If you change your mind you must return the product back to us within 30 days of delivery

Please include a copy of your invoice and a note stating reason for return.

Additional keys, locks keyed alike or built to code are non refundable as they are personalised made to order goods.

Any refund, which is due to a fault or other defect, will include a refund of the applicable delivery charges otherwise not.

It is the buyers responsibility to arrange the return of goods to us. We do not offer a collection service for returning items.

Items must be returned including original product packaging and accessories.

We reserve the right to refuse any returns that do not comply with this policy.

Please post returns to the following address:

Home Secure (Online)

Unit 5, Brookfield Drive

Liverpool, L9 7AJ

United Kingdom

Frequently Asked Questions

Security is identical — same 3-Star Kitemark, Sold Secure Diamond and anti-snap protection. The difference is inside your home: this version has a thumbturn instead of a keyway, so you exit by turning it rather than finding a key. If you'd rather need a key on both sides, choose the key-key version.

The cylinder itself carries exactly the same accreditations as the key-key AP. The consideration is your door: if a thumbturn could be reached and turned through a letterbox, cat flap or adjacent glazing, a key-key cylinder may be the better choice for that door. If you're unsure, send us a photo of your door and we'll advise.

If the external half of the cylinder is snapped off in an attack, the internal mechanism locks down to block the intruder — pressing the release button lets you still operate the lock from inside and exit the property.

The cylinder breaks at a sacrificial point and a patented interlocking mechanism locks the internals, preventing any further manipulation from outside — while the door stays openable from within.

It comes with 3 dimple/slider hybrid keys for the outside. Copies can only be cut to code through authorised centres, so keys can't be duplicated without your knowledge.