Please help What is this

[Panchito]

39 cm (15") long, brass nose stamped S&G there is a small blue ink spot midway looks like a oval with a line through the center weighs 7 pound 13 ounces.

 

[kahu1]

Looks like an early version of a SUS(Sound,Underwater Signal) marker.

Bob

 

[glevum]

Bob,

You beat me to it.

see http://www.bocn.co.uk/vbforum/threads/86922-RCAF-practice-bomb?highlight=sound+underwater+signal

Will.

 

[Panchito]

Thank you so much for the info. are they rare?