Here is the link for my Apple Motion Broadcast Countdown Clock. All the fields are customisable as is the face should you wish to put your company logo on there. It all works from 30 seconds onwards and cuts to black at -3. Please note there is a PAL 16:9 and a new NTSC 4:3 version as requested.

An essential tool for broadcast or corporate productions.

This clock was designed in Motion2 but works fine with Motion3