No. 700 Drill fuze.

[Quatermass]

British No.700 fuse for the 3" U.P. (unrotated projectile) AA Rocket

Thanks to Fuzeman for this additional information:

Rockets used in Shell, HE 3 inch No 1 Mk1
Action Pyrotechnic aerial burst
Arming time 1.2 seconds
Overall length 4.7 inches
Colour Brass


Fuze Mk 1 and Mk 2 are pyrotechnic time fuzes designed for anti aircraft purposes , variable settings from 0 to 30 seconds are obtained by rotating time setting ring . the time setting rings are graduated in 1/4 second intervals

 

[Quatermass]

Close up of the markings.

Quatermass

 

[Rrickoshae]

and a sectioned one