Hi,   I have a HP 420B Clip On DC Milliampmeter with Probe FS as I’mmoving in the spring.   Current measured goes from 1 mA FS to 10 Amps FS.   I have not used it since I bought it several years ago.  The reliable vendor who sold it to me had guaranteedthat it worked.  Will guarantee it isoperational.  I’ll also include a NOS6DJ8 input tube. The is some delamination on the meter faceplate of the whitebackground .  It does not contact themeter.   I also have a copy of the service manual.   $250 plus shipping from 92220   If interested please send me an ORIGINAL email because ifyou use the hyperlink on the address Yahoophoey will stack it up with otheremails which becomes a PITA to sort out.   Regards,   Perrier