OS Halo Timer 1.5 for Mac can be downloaded from our website for free. The application lies within Games, more precisely Tools. This free software for Mac OS X was originally created by One South.
From the developer:
For those of you that don't know about timers in Halo: Halo works by spawning items (such as power ups) that given time intervals despite when the item was picked up by a player and so this program will tell you when that item is spawning (literally will speak to you as well as many other methods of notification). For the program choose the map you are going to play.
You may want to check out more software for Mac, such as MAME OS X, HALO Magic Scanner or The Time Machine - Trapped in time, which might be related to OS Halo Timer.