Oladance Open-Ear Earbuds US$119.99 (~A$178, Save US$60) Delivered @ Oladance

These sit just outside your ears, so they let you stay aware of your surroundings. I have a pair which I use at home so that I can hear the kids calling/fighting/whatever while they can't hear the music/podcast I'm listening to. It's also handy for outdoor activities like bike riding if you want to listen to something but still hear approaching cars. It works pretty well.

From their website:

Feel the music, not your earbuds
This is the promise of the Oladance Wearable Stereos, the comfort-focused earbuds that deliver high-quality sound without ever going inside your ear.

• True Open-Ear Earbuds
• Up to 16 Hours Per Charge
• 16.5mm Dynamic Drivers
• Comfortable Fit
• Full Transparency
• Water and Sweatproof
• Zero Hearing Damage
• Clear Call