Developed by the Soviet Union as an amphibious scout tank, the PT-76 first saw NVA use against Laotian government troops at Ban Houei Sane on Jan. 23, 1968, after which it supported the Feb. 7 attack on the Lang Vei Special Forces camp. Highly mobile, the thinly armored PT-76 was no match for the M48 in combat and was vulnerable to air attack. The PT-76 at left, knocked out on the Plaine des Jarres in Laos, is being examined by a Thai forward air guide. (Michael Ingham Collection, The Vietnam Center and Archive, Texas Tech University)