Comparison
 Sperry-Remington 661-D |  Casio Mini CM-602 | |
| Manufacturer: | Sperry Rand Corporation (USA) | CASIO Computer Co., Ltd. (Japan) |
| OEM: | CASIO Computer Co. Ltd. https://www.qualityreplica (Japan) | https://www.replicafinewatches.me/ |
| OEM model: | - | |
| Mfg. date: | 1973 | 1973 |
| Size: | 8×15,4×4,1 cm | 15,3×8×3,5 cm |
| Weight (ready for operate): | 330 g | 340 g |
| Type: | four-function | four-function |
| Capacity: | 6 digits (input/display) 6 (12) digits (internal precision) | 6 digits (input) 2×6 digits (display) 12 (6) digits (internal precision) |
| Operating logic: | algebraic | algebraic |
| CPU: | Hitachi HD32154P + NEC uPD129C | Hitachi HD32154P + NEC uPD129C |
| Registers: | 2 standard (with saving the pending operation) | 2 standard (with saving the pending operation) |
| Features: | Fixfixed-point notation: the listed decimals can be chosen (0, 2) | Fixfixed-point notation: the listed decimals can be chosen (0, 2) |
| Display: | 6 digit VFD (6×NEC LD8085E) | 6 digit VFD (NEC LD8088) |
| Power: | 4×AA-type battery 6V adaptor | 4×AA-type battery AD-4145 adaptor |