About this product
One of the longest standing locks on the market and originally released in 1971 under the model name Impregnable. They are still made today using the same 'old school' high quality manufacturing techniques. Expensive yes, but reassuringly so.
Ingersoll used to be a family owned British company but since acquired. They continue to make a small but highly regarded range of padlocks which are still manufactured in England. This is unconfirmed but our suspicion is that they were originally made for Military contract and no found their way into the civilian market as a high security padlock.
NATO stock number (NSN): 5340991385224 and/or 534099504380
It is made from hardened steel which is graded in the UK and then finished in a dull nickel chrome plate to give it some weather resistance. This is important since imported steel from China can be of dubious quality. This is the closed shackle version which is design to help protect against force attacked. Bare in mind however that it will restrict fitting compatibility. Strangely, the mechanism uses levers rather than disc or pins which have, in recent times, been seen as less secure. That said this lock used 10 levers which is twice the number required by UK insurance companies for lever padlocks. Can it be picked? Highly unlikely.
Body and shackle are hardened so forget about cutting it. Drilling? Well as you can see from the image below there is a Z shaped anti drill bar preventing that and then a keyway cover that slides over the top.
Note that the lock is a closed shackle design and so it is restricted in terms of fitting. These dimensions when open might help you determine if it is suitable:
3 keys with every lock as standard. Note that you will not be able to easily get new copies made since the key blanks are not commonly stocked by high street locksmiths.
Interesting articles shwoing the release of the Impregnable Series back in 1971. Still the same high quality today.