Rings of speed

[Jbone]

Been on quite the Angband bender lately. I found my first ring of speed(+13) on DL52 after killing Itangast Fire Drake. This got me thinking, what are the odds that an enemy drops a ring of speed? They seem quite rare. I assume it scales with the DL but just curious how it all works

Thanks!

[Sky]

the math is complicated and i do not understand it, but in general items become much rarer the farther away they are from their native depth. On DL98, rings of speed are everywhere. The actual value of the bonus depends on a dice roll, and i believe that the depth affects this roll as well.