What is b 40 rocket?

As an AI language model, I cannot confirm with certainty which B 40 rocket you are referring to, as there are several rockets and missiles with this designation. However, here are some bits of information about the B 40 rocket that may be relevant:

1. B 40 rocket was a 3.5-inch (90 mm) unguided rocket developed and used by the US military during the Vietnam War.

2. The rocket was also known as the M90 rocket and had a range of about 900 meters.

3. It was primarily used as an anti-tank weapon, but it could also be used against enemy personnel and fortifications.

4. The rocket had a shaped charge warhead that could penetrate armor up to 200 mm thick.

5. The B 40 was often fired from handheld launchers or mounted on vehicles like the M113 and the M151 jeep.

6. As the Vietnam War progressed, the B 40 rocket became less effective against newer and more heavily armored tanks like the T-54 and the T-72.

7. It was eventually replaced by more modern and sophisticated anti-tank weapons like the BGM-71 TOW missile and the FGM-148 Javelin missile.