inputs.text: good value needs manual - device seehem function advertised note device not come 5 volt charger need provide one also note absolutely no instructions included no information providedclose examination appear show small metal looks similar ad584lh voltage reference mounted nice quality two sided pcb proper ground plane board also recommended layout thermal isolation ad584lh radial pattern holes board also silk screened ad584lh not id info printed top impossible verify made actually isthe seller includes small printed label bottom hand written measurehement data claims measured agilent 334401a meter keeping mind perfectly calibrated agilent 334401a expect measurehements within 00035 issue label handwriting pretty difficult read nice thehem includeafter warming device 30 minutes measured voltage reference using recently calibrated fluke 289 dmm voltages within 002 within stated measurehements course fluke 289 nowhere near accuracy agilent 334401a reference meter not bad seehem job fact device nicely packaged includes lithium ion battery nice touchmy reason not giving device 5 stars thy not include instructions information device think voltage reference good value need better support documentation otherwise seehems work advertised