This is the British 3kg, a practice Smoke & Flash aircraft-bomb with various Mks and numbered versions.
The 3kg practice Smoke & Flash-Bomb has been designed for use in practising those delivery techniques adopted for 454kg (1000lbs) retarded aircraft-bombs and 272kg (600lbs) cluster-bombs.

Under normal conditions, on Impact (IMP) with the ground or sea, the aircraft-bomb case remains intact and a Smoke & Flash signal is produced through the rear of the aircraft-bombs casing, similar to a rocket plume.

An inert variant without the Smoke & Flash is available and is designated 3kg No 2 Mk 3 practice aircraft-bomb.

Two practice aircraft-bomb carriers have been developed the Carrier-Bomb-Light-Store (CBLS) 100 and the CBLS 200, which were designed to carry up to four practice aircraft-bombs each.

The aircraft-bomb is light-blue fibre-glass.