Jabra has nice options if you're interested in lightweight wireless headphones (the Jabra Move Wireless - see previous post), and a similar answer for Bluetooth phone headsets -- the Jabra Stealth headset.
The Stealth is a particularly small and discreet design -- basically a thin rod that weighs about a quarter ounce.
The small size does not skimp on sound quality. Its Jabra sound enhancement technologies include Noise Blackout and dual microphones to reduce background noise, and HD voice for high definition sound quality.
You can fit the Stealth in your ear with different ear gels, with and without a flange to anchor in your ear folds, or add an optional earhook if desired for additional support.
In addition to the power and call answer/end buttons, smartphone voice control has become so important that the Stealth also adds a dedicated Voice button on the side for voice dialing and commands, using Apple's Siri or Google Now.
The headset provides voice guided instructions for status and for pairing, or use NFC. There's also a Jabra Assist app for Android and iOS that provides GPS tracking of the headset, pairing assistance, and headset battery status.
It charges in about two hours to provide up to 6 hours of talk time, or 10 days of standby.
The small but impressively capable Jabra Stealth is available for around $99.
Find the Jabra Stealth Headset on Amazon.com