The Twenty is a simple solution to a complex problem: How can you add wireless connectivity to existing, non-wireless speakers? Pretty enough to live in plain sight, the 20-watt amp boosts each audio channel, hooks up to old-school speakers, game consoles, TVs and other devices with cables. But it can also communicate with smartphones, tablets and computers via Bluetooth. The Twenty’s best feature is its stripped-down design: When you press the solitary button up front, it pairs with any device within 30 feet and can hop from one gadget to the next with each push. Anyone who’s dealt with Bluetooth speakers accidentally talking to the wrong gear should appreciate this feature. And the amplifier’s volume can be controlled with the top-mounted aluminum knob, a straightforward interface choice that’s also satisfyingly old-school analog. $150; http://store.griffintechnology.com