Sony Vaio Tap series use the active digitizer technology from N-Trig (bought by Microsoft). The tablet screen contains a special digitizer layer to interact with the corresponding N-Trig active stylus tip. So, as long as it is N-Trig powered active stylus, it will work fine.
You don't need to buy exactly the pen from Sony. You can use the active stylus Surface 3 ( 2 and 1 will not work as it's not N-Trig, but Wacom) who utilize the same N-Trig digitizer technology.
All those N-Trig pens (from Sony, Surface 3) all the same. In fact, it is just the bare-bone N-Trig active digitizer painted differently. ;) Some pens like the Surface 3 pens will have another electronic part (the little top with a pink button) that works separately from the pen itself and provides additional features like opening OneNote...
When buying, you can bring your tablet along and test the pen to see if it works. Simply hover the pen above and near the screen, and there should be a tracking dot appear on the screen corresponding to the pen's tip. Another way would be to check the specification to see if the pen is N-Trig.
PS: I've heard of a solution that is to check whether the pen is battery-powered, to determine if the pen is N-Trig. This is not quite true: Wacom pens are always battery-less, but N-Trig and Synaptics are both battery-powered!
Sure; Just install the drivers for the pen. – Ramhound – 2014-10-01T02:58:36.697
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I'd guess not - Apparently its an active stylus using something called n-trig. The screen is capacitive so for basic use any capacitive stylus should work. For full pressure sensitivity, you'd need a specific type of active stylus. However this is apparently pretty common, and a stylus using the same technology should work, in theory. I'm not 100% sure tho
– Journeyman Geek – 2014-10-01T03:03:47.223Any pen of the same type would work, there are multiple n-trig pens, the driver should be enough – Ramhound – 2014-10-01T03:10:28.363