| 6644A-0B3 | English Printed Service Manual |
| 6644A-0L1 | English Printed Users and Programming Guide (full documentation on CD-ROM) |
| 6644A-100 | 87-106VAC operation, 50/60Hz |
| 6644A-120 | DC power supply 104-127VAC operation, 50/60Hz |
| 6644A-220 | 191-233VAC operation, 50/60Hz |
| 6644A-240 | 209-254VAC operation, 50/60Hz |
| 6644A-A6J | ANSI Z540-1-1994 Calibration |
| 6644A-J09 | |
| 6644A-PLG | Continental European power cord - only for EU DISTR W MULT PWR CORD standards |
| 6644A-S50 | Non-latching remote inhibit |
| 6644A-UK6 | Commercial calibration certificate with test data |
| 1CM002A | |
| 1CP001A |
请与是德联系，了解选项定价。
| R-50C-011-3 | Calibration Assurance Plan - Return to Keysight - 3 years |
| R-50C-011-5 | Calibration Assurance Plan - Return to Keysight - 5 years |
| R-50C-011-MU-3 | Keysight Calibration + Uncertainties - 3 years |
| R-50C-011-MU-5 | Keysight Calibration + Uncertainties - 5 years |
| R-50C-021-3 | ANSI Z540-1-1994 Calibration - 3 years |
| R-50C-021-5 | ANSI Z540-1-1994 Calibration - 5 years |
| R-51B-001-5Z | Warranty Assurance Plan - Return to Keysight - 5 years |
请与是德联系，了解选项定价。
