McGrath Ultra Secua & Triple Lock Kits – What Works, What Doesn’t & Installation Advice
Posted by Mat Steele on 10th Feb 2026
McGrath UltraSecua & Triple Lock Kits
What works, what doesn’t — and when professional installation matters.
The McGrath UltraSecua is a purpose-built smart lock designed specifically for hinged security screen doors. The question we hear most often is: “I have a triple-locking screen door — will the UltraSecua work with it?”
The answer is: sometimes yes, sometimes no — and the determining factor is almost always whether your triple lock kit uses rods or cables. Jump straight to the cables vs rods rule if that’s all you need.
This guide covers which triple lock kits are compatible, what’s involved in the installation for each brand, and when removing the triple kit entirely is actually the better outcome. It applies equally to both UltraSecua variants:
- McGrath UltraSecua (standard) — independent screen door operation
- McGrath UltraSecua Dual Unlock — screen door + main door unlock together
Not sure which version to choose? See What Dual Unlock Actually Does in our Dual Unlock guide.
This guide was reviewed and updated in May 2026.
The Two UltraSecua Models
Both models share the same lock body and the same triple lock compatibility. The only difference is the Dual Unlock function.
Door Compatibility — Read Before Installing
Designed For- Hinged security screen doors
- Aluminium framed hinged screen doors
- Standard and triple-locking screen doors (conditions apply)
Not Compatible With- Sliding screen doors
- Sliding glass doors
- Hinged glass doors
- Any door without a hinged, swinging action
Understanding Triple Lock Kits
A triple (or 3-point) locking system secures a hinged screen door at three points simultaneously when the handle is turned or the key is operated:
- Centre lock — the primary mortice lock body at handle height
- Top locking point — a bolt or hook that engages the door frame near the top
- Bottom locking point — a bolt or hook that engages the door frame near the bottom
The centre lock drives the top and bottom points through a mechanical linkage — either rigid rods or flexible cables. The type of linkage used is the single most important factor in whether the UltraSecua will work with your existing kit.
The Key Rule: Cables vs Rods
Cable-Based Kits — Not CompatibleCables use tension to pull locking points in one direction. The UltraSecua requires a positive push-pull mechanical action to drive the top and bottom bolts in both directions. Cables flex under compression and cannot reliably transmit force in both directions, meaning the locking points will not operate correctly.
Rod-Based Kits — CompatibleRigid rods transmit mechanical force in both the push and pull directions. When correctly installed and adjusted, rod-based kits provide the positive engagement the UltraSecua mortice requires to drive the top and bottom locking points reliably.
How to Identify Your Kit Type
You can usually identify cable vs rod without removing any hardware. Open the screen door and look at the linkage running between the centre lock body and the top and bottom locking points:
- Cables look like thin flexible steel wire, often running through a plastic or metal conduit. They flex when you push them sideways.
- Rods are rigid straight metal bars, typically 5–8mm in diameter. They do not flex when pushed sideways.
Brand-Specific Installation Notes
Cable-based Austral kitsNot compatible. The cable linkage cannot provide the positive push-pull engagement required.
Rod-based Austral kitsCompatible when installed and adjusted correctly. Rods provide the positive engagement the UltraSecua requires.
Check the linkage type before ordering. The rod-based Austral installation is the most straightforward of the three brands covered here. See the installation video below for a step-by-step walkthrough.
The Whitco Tasman MKII is a known compatible triple kit. However, it is not a simple bolt-on retrofit.
Professional installation is strongly recommended. The Whitco-specific video below shows the process in detail.
Lockwood triple kit installations are the most involved of the three brands. With many Lockwood kits, the entire triple lock assembly must be removed and reinstalled in reverse.
This is a complex, time-consuming installation. It is not a DIY job. The Lockwood-specific video below shows what’s involved.
Professional Installation — Why It Matters Here
Triple lock retrofits are not straightforward DIY jobs. Unlike a standard single-point lock swap, these installations typically involve:
- Disassembly of the existing triple lock mechanism
- Reassembly in a modified or reversed configuration
- Precise rod adjustment — too long or too short and the locking points won’t engage cleanly
- Strike plate relocation on the door frame
- Potential door removal, drilling, and frame modification
A Practical Alternative: Remove the Triple Kit Entirely
In many homes, the simplest and most reliable outcome is to remove the triple lock kit entirely and install the UltraSecua as a single-point mortice lock.
The triple lock adds extra bolt points, but the UltraSecua’s own mortice lock with the screen door’s frame provides excellent resistance in practice. Your locksmith can advise whether keeping the triple points is worth the additional installation complexity for your specific door and situation.
Official Installation Videos
McGrath Locks has produced installation videos for each of the three triple lock brands. These are worth watching before beginning any installation — and essential viewing for a DIY attempt, though professional installation is still recommended for all three.
Frequently Asked Questions
Is the UltraSecua suitable for sliding doors?
No. It is designed exclusively for hinged security screen doors. For sliding screen and glass doors, different products apply — see Chapter 04 — Door Type Matching.
Can I keep my triple lock?
If rod-based, usually yes — but modifications are typically required. If cable-based, no. See the cables vs rods rule above. In some cases, the single-point alternative is the better outcome.
Will door modification be required?
Often yes. Strike plate relocation, drilling, and cutting are common for Whitco and Lockwood kits. Austral rod-based installs are typically less invasive.
Does this blog apply to both UltraSecua models?
Yes. The standard (MLULSBKWM) and Dual Unlock (MLULSDUBKWM) versions share the same lock body. Triple lock compatibility is identical for both. The choice between them is about whether you want the screen door to unlock independently or in tandem with your main door — see What Dual Unlock Actually Does.
Related Guides
Single-point screen door control — IP66, PIN/RFID/Bluetooth/key, 28mm backset. The standard non-Dual Unlock version.
Same body as the standard model, with added Dual Unlock — coordinates with your main entrance door lock for single-action entry.
If you want both doors to unlock together rather than independently, this explains the feature and both products that offer it in Australia.
Before ordering any smart lock for a screen door setup, confirm the clearance between your screen and main door. A critical pre-purchase check.
Triple lock retrofits are among the more complex screen door installs — a professional assessment before purchase ensures the right outcome.
Full compatibility matrix for all Australian door types — hinged screen, sliding screen, timber, aluminium, fire, glass, and more.
Not Sure What Triple System You Have?
Send us photos of your existing lock and the linkage area inside the door edge — we’ll identify whether it’s cable or rod, and what the installation will involve, before you purchase anything.
Ask an ExpertVisit Australia’s leading Smart Lock showroom and workshop:
Gold Coast Smart Locks
9/2 Prosper Crescent
Burleigh Heads, QLD
See working models and get installation advice from locksmiths who’ve handled every triple lock scenario.
