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Sillcock Keys and other Cross Keys: What are they for?

Sillcock Keys and other Cross Keys
Sillcock keys and other multifunction cross keys are commonly used by contractors and engineers who service various commercial and industrial equipment. So why is that important? Well… If you experience a SHTF situation in an urban environment, there are many reasons why you might need to open something that requires one of these special keys. In this article, I’ll go over some of the most common 3″ x-n-1 cross keys and explain what they could be used for…

Sillcock KeyThe Sillcock Key
A sillcock is an outdoor water spigot, hose bibb, faucet or valve that is attached to the exterior of a residential, commercial or industrial building. Residential sillcocks most commonly have a handle or lever to control the flow of water. But commercial and industrial sillcock valves typically require a key to operate them, primarily as a deterrent of vandalism. Not having a handle readily available prevents would-be vandals from turning the water on and leaving it running, possibly flooding the area. Sure, you might be able to open some sillcock valves with pliers or a multi-tool, but most are engineered to protect against them.

Sillcock keys are four-way cross keys with an overall dimension of 3″ square, and a little over 5/8″ thick. The Sillcock Key shown is made from an extremely tough heat-treated steel alloy so it weighs 5.5 ounces. Not at all light, by any means… I would love to see one made from a lighter material like titanium or aluminum, but I am sure the cost would be very high. Each of the four female ends fits a different square valve stem in one of the following commonly found sizes: 1/4″, 9/32″, 5/16″ and 11/32″. Sure, there are valve stems in other sizes, but these four are by far the most common.

So why would you want to keep one in your EDC or Bug-out bag? In an emergency or grid-down situation in an urban environment, the supply of water may become disabled making water difficult to find. In commercial and industrial buildings, water pipes are most often overhead. As a result, water may become trapped in the pipes through air-lock or gravity, even without pressure. And this water would only be accessible via the sillcock valves in key locations inside and around the perimeter of most buildings.

4-n-1 Control Cabinet Cross Key4-n-1 Control Cabinet Cross Key
The Universal 4-n-1 Control Cabinet Cross Key is a very common multifunctional cross key, used by electrical and HVAC contractors, electrical and mechanical engineers, and building/facility maintenance professionals alike.

The key features a double-bit paddle key with a 5.0mm internal diameter hole and a 9 mm external diameter shaft that is commonly used to open electrical panels, control cabinets, meter boxes and service panels, as well as elevator and train door control panels. It also includes a 9 mm female triangle key and two square female keys for operating many water and gas shut-off valves in both 6 and 8 mm sizes.

My key, pictured here is a rugged cross key made from a lightweight die cast zinc alloy so it weighs only 1.7 ounces. While I’ve seen many 4-n-1 Control Cabinet Keys from other manufacturers made from other materials including aluminum, steel, and stainless steel, most are made from a similar zinc alloy as the one that I have here from QST.

5-n-1 Switch Cabinet Cross Key5-n-1 Switch Cabinet Cross Key
Another common multifunctional cross key is the Universal 5-n-1 Cross Key Wrench also from QST. It is commonly used for opening and closing of air-conditioning and revision system controls, locking of bins and waste containers, and street lamp lids. Like my other keys from QST, this key is also made from die cast zinc alloy so it is lightweight and very durable.

This key is very similar to the Universal 4-n-1 Control Cabinet Key listed above, but with a few significant differences. The most prominent of them being the missing double-bit paddle key. This key instead features a stepped male key in 6, 7, 8 and 9 mm -square sizes. The second, the plastic adapter that allows the cross key to use 1/4″ bits like the 1 mm x 7 mm slotted head and cross-head Phillips #2 reversible bit that was included.

This 3″ cross key also includes a 9 mm female triangle key like the one above, and also three square female keys for operating many water, gas and steam shut-off valves in 5, 6 and 8 mm sizes. Altogether, the key, plastic adapter, and included bit weigh a total of 2.2 ounces.

10-n-1 Control Cabinet Cross Key10-n-1 Control Cabinet Cross Key
Ten tools in one… Why not? The Universal 10-n-1 Control Cabinet Twin-Cross Key from QST-CAIDU is just that. A universal key for actuating of locking systems on control cabinets and service panels.

It contains all of the common keys in one so contractors, facility managers, and maintenance professionals can carry a single key to gain access behind inside control cabinets and behind service panels.

Both cross keys are made from a lightweight die cast zinc alloy and held together using a set of strong magnet discs, and a 6″ braided stainless steel wire which also holds the 1/4″ reversible hardened steel screwdriver bit securely attached. The bit has a 1 mm x 7 mm slotted head on one side, and a Phillips #2 bit on the other. Combined, the two keys along with and screwdriver bit weigh a total of 4.9 ounces so it is easily packable.

Between the two keys, there are four square female keys in 5, 6-7, 8-9 and 10-11 mm sizes, three triangular keys in 7-8, 9-10, 11-12 mm sizes, one 6 mm half-moon key, and a stepped male key in 6, 7, 8 and 9 mm -square sizes. If you work in large buildings or industrial complexes, a key like this could be very helpful if you needed to escape in event of a serious emergency.

6-n-1 Cleanout Plug Wrench6-n-1 Cleanout Plug Wrench
The most unique multifunctional cross key that I have has to be a heavy 5.5″ Universal 6-n-1 Cleanout Plug Wrench from Pasco. I stumbled upon it years ago when I first got into plumbing, and I have never seen one like it since. It is made from a solid cast iron and rugged as hell so it is no wonder that it weighs nearly 2-1/2 pounds, which basically means that it is certainly not something that you’d ever consider carrying it around. But it could be a very useful cross key in a grid-down situation because of what it can be used for.

The key features two male slot keys in 1″ x 3/8″ and 1-1/2″ x 1/2″, and four square male keys in 3/4″, 1″, 1-1/8″ and 1-3/8″. These are used for opening flush-mount water, gas, electrical and sewer pipe plugs commonly found in commercial and industrial facilities.



If you live or work in an urban area and there is a catastrophic emergency causing a grid-down situation, being able to access water left in pipes when there is none around, or mechanisms that control the operation of mechanical doors, and even access to materials like wire that could be used could be used for escape or survival, could make all the difference between life and death. Keys like the ones that I discussed in this article should be at least considered when you are putting together your emergency plan. Especially the Sillcock Key. Sillcocks and hose bibs that are hidden in service panels located around the outside of commercial buildings are far too common not to be considered.

But as an experienced plumber for most of my life, I do find it rather humorous when I hear people say they will just use a plain old multitool to open sillcock valves and such. The fact is that many of these valves and locking mechanisms have never been opened, or they are opened so rarely that they are more than difficult to open, even with the right tool for the job. Don’t fool yourself into thinking you don’t need one if accessing them in this way is, in fact, part of your survival plan.



  • Gerren Rabideau

    Yeah, but overall which one do recommend carrying if you can only carry one?

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