Eclipse viewing glasses:
These are the only way of viewing the eclipse directly, other than through a telescope fitted with a professional filter. Similar to 3D glasses, eclipse viewers are made from card and inlaid with a special material that cuts the Sun's light down 100,000 times. If using a viewer, check for holes or scratches as it is only safe if undamaged.
Eclipse viewers are being given away free with the Society for Popular Astronomy's members' magazine and the BBC's Sky at Night magazine.