A gold-colored metal window lock mechanism with an offset espag, positioned against a plain background.
Technical drawing of a metal strip with two mounting holes spaced 43mm apart, showing dimensions including 8mm thickness, 16mm width, and a customizable length and backset (20mm or 25mm).
Diagram showing two types of UPVC window gearboxes: Offset Gearbox on the left and Inline Gearbox on the right, with red window profiles and labeled parts for comparison.
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A gold-colored metal window lock mechanism with an offset espag, positioned against a plain background.Technical drawing of a metal strip with two mounting holes spaced 43mm apart, showing dimensions including 8mm thickness, 16mm width, and a customizable length and backset (20mm or 25mm).Diagram showing two types of UPVC window gearboxes: Offset Gearbox on the left and Inline Gearbox on the right, with red window profiles and labeled parts for comparison.

UPVC Window Lock - Offset Espag - 400mm – Replacement uPVC Window Part

AvocetSKU: HS2663
162 reviews from verified buyers
Price:
£7.49

Key benefits

  • Offse espag mechanism - fits older offset-pattern windows
  • 250mm to 800mm lengthst - match your window height
  • Direct replacement - fits most older uPVC windows

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Description

This is the mechanism inside the window frame that is operated by the handle

Gearbox is positioned over to one side on the rail (offset)

Important Measurements

1) Overall length

2) The 'Backset' (20mm, 25mm)

4) Rail Width (Usually 16mm)

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Frequently Asked Questions

A 400mm offset espag window lock is a multipoint locking mechanism designed for uPVC windows with an off-centre handle spindle position. It helps secure the window by engaging locking points along the frame.

The 400mm measurement indicates the overall length of the espag mechanism. Matching this size with your existing lock is important for proper fit and smooth operation.

Signs of a failing espag include difficulty turning the handle, poor locking performance, stiffness, or the window not closing securely.

No, compatibility depends on the spindle position, backset, and dimensions of your current mechanism. Always compare specifications before ordering a replacement.

Choosing the correct mechanism depends on your window type, size, and locking configuration. To learn more, read: How to Choose the Right Window Mechanism: Friction Stays & Espagnolette