They were a little over 6' tall, more than 1/3 of it explosive charge. If you heard them overhead they were no threat. If they came close you heard a screaming rocket engine just before the explosion. Not enough time to do anything except die a little inside. In our basecamp full of rubber trees, a tree-burst 100 yds. away could kill you. This was the most effective psychological weapon that the VC/NVA used against us. They were seldom used before Tet, but there seemed to be an inexhaustible supply during the Tet Offensive. It brought the war home to American basecamps. Lai Khe and other basecamps which were mostly surrounded by jungle were especially vulnerable, because the enemy could get close to launch and it was difficult to detect launch sites.