The telescopic pin system has been around a while and mainly used by the mul-t-lock brand although there are others such as the avocet abs that use the same design combined with a magnetic pin element.

They are generally considered high security locks and require special tools to open, however i have found that these locks with a little practice will open just as easilly with the correct half diamond pick.

My weapon of choice is the larger half diamond found in the southord pick set.

Resting the flat edge of the pick in the narrowest corner of the keyway should place the tip of your hook directly above the pinstacks and all thats needed to set them is a slight rotation of the pick ensuring the flat edge remains in that corner of the keyway.

Combined with featherlight tension you can open these locks in a few minutes.

Note: the avocet abs requires a small section of fridge magnet to lift the magnetic pin, although the same can be achieved by magnetising the pick blade itself.

Here a few i did earlier:

 Rick - Walsall Locksmiths