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LB23 - 12 inch Narrow Letterbox

From £23.53
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From £23.53
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Aluminium 12 inch Narrow Letterbox

  • Suitable for upvc or aluminium doors with narrow frames.
  • All metal surround and letterplate made from aluminium.
  • Foam seal/pad fixed to flap to stop draughts and leaks.
  • Strong springs means non-rattle.
  • Actual sizes are 317mm x 50mm.
  • Help video: How to fit a upvc letterbox
  • Help Guide: How To replace a letterbox for uPVC Door
  • FAQs: Customer questions about replacement upvc letterboxes
  • Detachable telescopic sleeves (40-80mm door thickness) mean you can just attach the front and back plates or clip the sleeves into place for a fully enclosed postal slot.
  • Self tapper screws provided for upvc for an easy fix (screw straight into your door).
  • Not suitable for coastal designated areas. Please contact for more details.

12 inch Narrow Letterbox General Information


Hole through the actual sleeve of the unit is 260mm x 30mm with 292mm fixing centres. Postal slot on your existing letterbox can be between 280mm x 40mm max.


A robust UK manufactured slimline 12 inch narrow letterbox for use with PVC and aluminium double glazed doors. An all metal construction surround and plate give this letterbox a real quality feel! The flaps are designed to open to 95 degrees and this narrow letterbox will even take A4 post comfortably!

A lot of the old aluminium double glazed doors used this narrow slimline letterbox as standard so this model provides an ideal replacement. Due to the narrowness of the letterbox the postal slight is somewhat challenged to provide sufficient space for an adequate level of post which is why the brush seal is left out of this design. The weather sealing performance is however not compromised as the outer letterplate flap contains a thick foam pad which provides a seal against window and rain ingess when closed.


One of the big features of this 12 inch narrow letterbox is the detachable sleeve. The letterbox unit comprises of two halves of the inner sleeve which slide within one another when the letterbox is together but they can be detached if not needed, or even if you want to cut down the length of the sleeve as this will be easier to do. This leaves you free to consider using just the letterplates each side.

Video: Watch a short product demonstration of this product and its unique detachable sleeved letter plate.



To fix this letterplate to the door requires only the use of a self-tapping screw for upvc (supplied) or if a double glazed aluminium door then rivets can be used. The screw holes are positioned centrally at 292mm centres.



It's easy to look after this letterbox by cleaning with a dry cloth. It needs nothing more than that so please avoid any chemical cleaners as they are needed and can degrade the finish. 

Not suitable for coastal designated areas. Please contact for more details.

Royal Mail Update:

Please note that Royal Mail will be striking on Wednesday 30th November and Thursday 1st December. Orders placed using Royal Mail services from 2pm Monday 28th November until 2pm on Thursday 1st December will be affected. Please read the changes below and note that an alternative carrier will be available during this period and can be selected in the cart.

*Strike action upgraded to 24hr is in operation i.e. all 2-4 day service Royal Mail parcels will be upgraded to a 24 hour RM service during the period above. This does not mean the parcel will be delivered within 24 hours but will ensure it takes priority.

**All orders over £100 will be FREE carriage using the DPD Next Working Day service during strike action days.

We apologise for the inconvenience. Further details will follow nearer the time. For more details please visit the Royal Mail Help Page.

Please note last dispatch for the day (Mon-Fri) is 2pm, so your order forwards on to the next day for dispatch if your order is placed after this time. Orders placed after 2pm on Friday are dispatched on the Monday.

Channel Islands: VAT is removed on the final steps through the basket and is not charged to CI postcodes.

European Deliveries are currently suspended.

The following special offers are available to you when you buy the 12 inch Narrow Letterbox. The discount for the special offer will show in the cart if both the 12 inch Narrow Letterbox and the special offer product are added.

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