| Model No | HPD-A20 | HPD-A21 |
| Wavelength range | Single wavelength ( 190 to 800 nm ) | Dual wavelength ( 190 to 800 nm ) |
| Wavelength accuracy | ± 0.5 nm | ± 2 nm |
| Wavelength repeatability | 0.15 nm | 0.3 nm |
| Band width | 8 nm | 8 nm |
| Optical path | 10 nm | 10 nm |
| Deuterium lamp | 190 to 400 nm | 190 to 400 nm |
| Tungsten lamp | 400 to 800 nm | 400 to 800 nm |
| Baseline noise ( Static ) Au | ≤ ± 0.35 × 10-5 | ≤ ± 0.5 × 10-5 |
| Baseline drift ( Static ) Au / h | ≤ 1 × 10-4 | ≤ 1.5 × 10-4 |
| Minimum detection limit | ≤ 4 × 10-8 | ≤ 4 × 10-8 |
| Power | 100 W | 100 W |
| Power supply | 90 V / 50 to 60 Hz | 90 V / 50 to 60 Hz |
| Dimension | 460 × 315 × 180 mm | 460 × 315 × 180 mm |
| Weight | 9.5 kg | 9.5 kg |