Got this, can someone tell me what is written below means: Real Cetron tubes made in USA or... Date manufactured year 2002 or 1952 ? Thanks in advance, 73 de Osten SM5DQC e-mail: sm5dqc at algonet.se >> The 572B are CETRON distributed by National Eletronics Cetron >> is part of the National group, batch code printed on base 572B/T160L >> 0252