The straps are elastic with beads so that they can be adjusted and they go behind the ear.
All masks are made of 100% polyester with a pocket where you can add a filter if you want.
These are the average sizes for the masks:
• Small - 8inches(width) x 4.5 inches (height i.e. from chin to nose)
• Medium - 8.5 inches x 4.75 inches
• Large - 8.5 inches x 5.25 inches
• Kids - 7.5 inches x 4inches
All straps are adjustable.