The third-age range coif is a member's only piece of armour that is part of the Third-age ranger set. To wear the coif, 65 Defence and 65 Ranged are needed. A third age range coif can be either obtained by chance with the completion of a Level 3 Treasure trail, bought from another player, or bought from the Grand Exchange. Because it is difficult to obtain, it is rarely seen in game.
It was long thought that the chances of obtaining a piece of third-age armour was of about 1 in 10,000 (according to Paul Gower), and in 2010 Mod Maylea stated that the odds are lower than 1 in 100,000 . However, a livestream with Mod Simon and James revealed the mechanics of Treasure Trail rewards in detail, meaning the actual chances could be calculated: approximately 1 in 16,896 per item roll for any of the 12 parts of third-age equipment, or approximately 1 in 202,752 for a specific part, per item roll - with an average of 5 item rewards per Trail, this gives approximately 1 in 3,380 for any part, or 1 in 40,551 for a specific part, per Trail completed. For a more detailed breakdown of drop mechanics and calculations, see Treasure Trails/Rewards#Hard.