HP 5350B Microwave Frequency Counter

HP / Agilent 5384A Frequency Counter Needs Power Button But Works

BK Precision 1823A Universal Frequency Counter 2.4GHz 3-Channel

Hewlett Packard Universal Frequency Counter HP 5334B Automatic Fall/Rise Time

Racal Dana 1992 Frequency Counter

Hewlett Packard 5316B 100MHz Dual Channel Frequency Counter IEEE‑488 6699

HP/Agilent 5316A 100 MHz Universal Frequency Counter w/1 GHz Option 003 & IEEE-4

HP Agilent Keysight 53181A / Opt: 010 Frequency Counter (225MHz)