This is the double piezo tweeter that is also used by Peavey UK in their Eurosys series speaker enclosures. I use it as a slap reproduction speaker for upright (rockabilly/swing) bass. While it's a piezo element with relatively high impedance, you should, in theory, be able to just hook it up in parallel with a (bass) speaker / woofer. I use a simple capacitor/resistor high pass filter thoug. A great feature of this tweeter is it's shape: while is is a retangle (rather than round), it's much easier to install in bass enclosures.
For rockabilly slap bass, these tweeters are GREAT. I would not recommend them for full range speaker enclosures where you want more than very high frequencies, better invest a little more in e.g. Peavey 14XT or 22XT drivers.
but that's not what I bought 'm for).