Changing out your insert is simple.
1. FACE THE DISC DOWNWARD AND AWAY FROM YOU.
2. HOLDING BOTH SIDES OF THE RING WITH YOUR FINGERS.
3. FIRMLY PRESS DOWN ON THE BACK OF THE INSERT WITH YOUR THUMBS.
It may seem snug, but we assure you, it is designed this way to stay in even amongst the coldest environments.
Tip: try pressing harder on one side to start the process of snapping the lens out.