Door Security Guards: Swing Bar or Chain, and How to Size Them

Updated 2026-11-05 · RAYEN 雷茵

What does a door guard do?

It lets you open the door a little and no further. You can speak to someone or take a parcel without giving them the door. A guard is a second line, behind the lock. It does not replace the lock, and it only works when someone inside has engaged it.

We list 5 door guards, in stainless steel and zinc alloy. They come in three builds.

Swing bar or chain: what is the difference?

• Swing bar. A hinged U-shaped bar on one plate folds over a ball stud on the other plate. The door then stops against the bar. The bar slides free only at the end of its slot, and that lines up only when the door is closed, so a hand from outside cannot reach it. Hotels often choose this build for that reason.
• Chain. One end of the chain is fixed. The other end has a stud that slides in a slotted track. When the chain pulls straight, the door stops. The gap depends on the chain length and on where you place the two parts.
• Enclosed restrictor. D3870 SN is a different build: the photograph shows a tube on a flange, a housing and a separate plate. Treat it as its own fitting and work from its drawing.

A swing bar gives a firm, repeatable gap. A chain is easier to fit where the door and frame do not sit flush with each other, because the chain takes up the difference. For a frame with a deep moulding, the chain is often the simpler choice.

What sizes are the guards?

• D3759 SS: stainless steel swing bar, 138 × 66mm, Brushed Stainless. The bar has a black sleeve, which also softens contact with the door and frame.
• D3760 SS: stainless steel chain guard, chain length 180mm, Brushed Stainless. The chain is sleeved too.
• D3871 SN: zinc alloy chain guard on long slotted plates, in Brushed Nickel, Antique Bronze or Brushed Zirconium Gold. Ask for the drawing for its plate sizes.
• D3870 SN: zinc alloy, in Brushed Nickel or Antique Bronze. Its sizes also come on the drawing.

A zinc alloy swing bar in Brushed Nickel or Antique Bronze is available too, if you need the bar build in a plated finish. Ask us for it and we send the drawing.

How do I check the fit on my door?

Close the door and look at the meeting line between door and frame. Both plates sit across that line, on the inside.

• The two faces must be close to level. If the frame moulding stands proud of the door, a swing bar may not sit flat.
• The screws must bite into the frame itself, not only into a thin trim. A guard is only as firm as what holds it.
• Fit it on the lock side, at a height the user can reach.
• On a metal frame, plan the fixing: a self-tapping screw and a wood screw are not interchangeable.
• If the door opens outward, tell us. We will look at it with you before you order, because the guard then works differently.

A worked example: a hotel room door in timber, opening inward, with a flat frame. The buyer wants a guard that looks the same on every floor and cannot be released from the corridor. D3759 SS is the first choice. Check that the 138mm length and 66mm plate clear the door closer arm and any frame moulding. Fit one on a sample door, open it to the stop, and judge the gap for yourself. Then fix the same height on every door.

A second example: a home with an older frame that sits proud of the door. Here D3760 SS is easier to fit, and the gap with its 180mm chain is set by where you fix the track.

What should you send us?

• A photograph of the closed door, from the inside, showing the meeting line.
• The door and frame material.
• Which way the door opens.
• The finish on the rest of the door hardware.

What to write on the order

Give the model, the material and the finish. For example: Security Door Guard, D3759 SS, stainless steel, Brushed Stainless, 138 × 66mm. State the screw type if your frame is metal. Quantities, price and delivery are confirmed per order. Browse the accessories, or send us a photo of the door and we will suggest a model.