New Possession Control Whistle
 

I don't know if someone has already posted something on this new whistle as I've been off-line lately. Looks like a good idea. I can't vouch for how they work. The PC-50 whistle

PC (Possession Control) 50 Whistle - Start Develop Finish

This is not a "new" whistle and many of the more seasoned officials here are not "fans" of this device.

If you use the "Search" feature, you will find a good many discussions about ways and recommendations to keep the arrow. Easiest, of course, is to have a competent table crew! (which many don't have in sub-varsity situations)

It is best to remember it yourself (if possible, takes practice). Others use the ole rubber band on wrist or whistle in pocket - which may be frowned upon in certain areas/associations.

Is That A Whistle In Your Pocket, Or Are You Just Happy to See Me ???
 

Frowned upon? Here, in my little corner of the Constitution State, it's considered a proper mechanic.