The short answer
A letterbox cowl (or visor guard) is a cover fitted to the inside of your door, over the back of the letterbox. It makes it harder for anyone to reach through or use a tool to fish for keys.
We no longer stock cowls. For the same job, we now recommend the FlapGUARD:
- A steel cover that locks
- Accredited to Sold Secure Domestic Bronze when fitted with its screws
- Post still comes through its 315 × 80mm opening
Letterbox fishing is when someone pushes a hook or rod through the letterbox to grab keys from the hall, or to work the inside handle. An internal letterbox guard is the simplest way to stop it. This guide explains what a cowl does, why we now recommend the FlapGUARD instead, and the other options if you also want fire protection.
What a letterbox cowl does
A cowl is a hood or box that screws to the inside of the door, around the back of the letterbox. Post drops down out of the bottom, but a hand or tool pushed through the letterbox meets the cowl instead of the hallway. That makes fishing for keys, or reaching the inside handle, much harder.
A cowl also cuts some of the draught through the letterbox, and stops people looking straight into the hall.
Why we now recommend the FlapGUARD
The FlapGUARD does the same job as a cowl, with three differences:
- It's steel and accredited. It's independently tested to the Sold Secure Domestic Bronze standard when fitted with the screws supplied.
- It locks. A turn-lock knob lets you lock it shut, for example at night or when you're away.
- Post still gets through. Letters and small packets pass through its 315 × 80mm opening.
It's also suitable for fire-rated doors, and fits most standard UK letter plates on uPVC, composite and timber doors.
Will a FlapGUARD fit my door?
- Overall size: 400mm wide × 100mm high × 20mm deep.
- Opening: 315mm wide × 80mm high.
- Check: measure the back of your letterbox on the inside of the door. The FlapGUARD needs to cover it, with flat door around it for the fixings. Our letterbox measuring guide shows you how.
How to fit a FlapGUARD
- Hold it over the back of the letterbox, on the inside of the door, and check the opening lines up and post can drop through.
- Choose your fixing. Use the four 20mm screws supplied for the strongest fit. The Sold Secure rating applies when it's screwed on. Or use the self-adhesive pads if you can't drill.
- Mark and fix it, then check it locks and unlocks with the knob.
- Post a letter through from outside to check it drops through cleanly.
Cowl, FlapGUARD or something else?
| Option | Stops fishing | Fire | Post |
|---|---|---|---|
| Letterbox cowl (no longer stocked) | Makes it harder | No | Drops out of the bottom |
| FlapGUARD | Yes, steel and lockable | Blocks items pushed through | Through a 315 × 80mm opening |
| Fire-retardant letterbox bag | Yes | Contains small fires | All post caught in the bag |
| Letterbox lock (2 sash jammers on the inside flap) | Yes, while fitted | Blocks items while fitted | No post while locked |
Our best-selling letterbox security is the fire-retardant letterbox bag, which suits doors where fire, fireworks or anti-social behaviour are a worry as well as burglary. For a full comparison, see our guide to preventing letterbox burglary.
The free fix: keys and handles
Whatever you fit, keep keys out of reach and out of sight of the letterbox. Lift the handle and lock the door with the key every time, even when you're in. A tool through the letterbox can push a handle down, but it can't turn a key.
Need help?
Send a photo of the inside of your letterbox to info@homesecureshop.co.uk, or call us on 0151 521 8089, and we'll tell you what will fit.
