What can I put in my W540's mini Expresscard slot?

[Weboh]

I have a W540. It has an expresscard slot that the specs say is also a smartcard slot. https://www.lenovo.com/us/en/laptops/th ... ries/w540/I don't need a smart card (which is just for security as I far as I can tell). Does this double as an expresscard slot? If so, what kind of things are available to expand it? The only thing I can think of offhand that I would use is an HDMI output, if such a thing is available as a smartcard. Google seems to say no.

What do you guys think? What kind of mini expresscards do you use to expand your Thinkpad's features?

[RealBlackStuff]

A Smartcard slot sits on the right side, near the front, directly under the palmrest.
An Expresscard slot sits on the left side, near the front, directly above the laptop bottom.
You can have none, either or both.

[Weboh]

Okay, then it's a mini Expresscard slot.

[sebileis]

ExpressCard is more of a legacy slot that Lenovo sadly did away with after the P51/P71. It allowed you to add expansion cards to your laptop (Firewire, card readers, USB 3.0, capture cards, etc) and I use it on my W540 to hook up a few legacy peripherals that I otherwise couldn't plug in directly. Nowadays people in the ThinkPad community are coming up with alternate uses for the slot, such as for using external graphics cards, NVME SSDs, and more. In a way you could see it as a predecessor to Thunderbolt in terms of allowing you to expand your laptop and the bandwidth the slot provides.