Expresscard USB 3.0 adapter?

[fessen]

MacBook Pro 5,2 (early 2009 17) on Snow Leopard, but switching to El Capitan soon.

Anyone successfully using an Expresscard-to-USB 3.0 adapter?

None of the adapters I see advertised on Amazon, such as those from StarTech, Gmyle, Sabrent, US Robotics, and Monoprice, are described by the sellers as supporting OS X.
There are comments and reviews from some users of a few of those models that worked with third-party drivers.

 

[fessen]

Found this product from Sonnet Tech. Might be worth a try. They advertise it as supported under 10.8.5+ (and including El Capitan), as well as various Windows versions.
USB3-2PMA-E34 USB 3.0 ExpressCard/34

Not exactly cheap at the manufacturer's store, at $50 plus shipping, but maybe an independent distributor has lower prices?

Addendum - lot of bad Amazon reviews. Too expensive to chance it.