Comparison
 Sperry-Remington 661-D |  Canon Palmtronic LE-10 | |
| Manufacturer: | Sperry Rand Corporation (USA) | Canon Inc. (Japan) |
| OEM: | CASIO Computer Co. Ltd. https://www.qualityreplica (Japan) | https://www.ukomegasec.co/ |
| OEM model: | - | |
| Mfg. date: | 1973 | 1972 |
| Size: | 8×15,4×4,1 cm | 8×14,5×4 cm |
| Weight (ready for operate): | 330 g | 435 g |
| Type: | four-function | four-function |
| Capacity: | 6 digits (input/display) 6 (12) digits (internal precision) | 10 digits (input/display) 10 digits (internal precision) |
| Operating logic: | algebraic | algebraic |
| CPU: | Hitachi HD32154P + NEC uPD129C | Texas Instruments TMC1824NC + TMC1825ANC |
| Registers: | 2 standard (with saving the pending operation) | 2 standard (with saving the pending operation) 1 constant (with saving the pending operation) |
| Features: | Fixfixed-point notation: the listed decimals can be chosen (0, 2) | Ffloating-point notation |
| Display: | 6 digit VFD (6×NEC LD8085E) | 10+1 digit LED |
| Power: | 4×AA-type battery 6V adaptor | rechargeable battery pack |