Accurate measurement
When accurate measurement is essential you can rely on Timer.
When accurate measurement is essential you can rely on Timer, in addition to accuracy, you will find a lot of useful features: the stopwatch lets you check elapsed time using the Lap property; the timer can be optionally repeated so that you can specify an action occurring after a specific amount of time or an action that repeat every specific amount of time; the alarm clock allows you to choose between the 12-hour format or the 24-hour format and optionally can show you the remaining time; the clock is a convenient watch with large digits with, optionally, the indication of the current date.

Programmable actions
Play alarms with your favorite sound, display a message defined by you, speak a message…
Programmable actions include play alarms with your favorite sound, display a message defined by you, speak a message, announce the time, and a lot of more actions available as Pro features as: play iTunes files or iTunes playlists and stop iTunes; sleep, restart, shut down the computer; launch and quit an application; open a file; run an AppleScript file script; launch a web address and send an email with custom text and optional tags as current local time, running processes (visible or invisible), current application log. The included default actions are: play alarms with your favorite sound, display a specific message, speak a specific message and announce the time.

Pro features
Timer is free to use but there is also a Pro version which includes some additional features.
Timer is free to download and you can freely use it as long as you wish, although some users may be interested in buying the Pro version which includes some additional features: Full-Screen Mode, Iconized Windows, Open an Unlimited number of Windows, Play iTunes Song, Play iTunes Playlist, Stop iTunes, Sleep Computer, Log Out User, Restart Computer, Shut Down Computer, Launch Application, Quit Application, Open File, Run AppleScript File, Launch Web Address and Send Email. The option to purchase the Pro version is offered in the free version.

Many reasons to use Timer
Simple to use but powerful in functionality.
    Professional stopwatch, alarm clock, timer and clock utility for Mac.
    Easy-to-use and intuitive interface with clear tab-based browsing.
    Accurate measurement with tenths of a second.
    Stopwatch with elapsed time.
    Repeating timer to have an action that repeat every specific amount of time.
    Choose between the 12-hour format or the 24-hour format for alarm.
    Programmable actions as play alarms, display a message, speak a message, announce the time.
    Optional Pro features as Full-Screen Mode, Iconized Windows and Unlimited Windows.
    Optional Pro actions as Run AppleScript Files, Launch Web Addresses and Send Emails and so on.

Requirement: Mac OS X 10.5 or later

Home Page - http://www.apimac.com/mac/timer/