The user's manual for the D4 is not available (yet) on Suunto website. However, Google indicated its availability on the Aqualung one.... the full one (100 pages).
http://www.aqualung.com/technical_li...en_highres.pdf
Here are the differences found in the user's manual between the D6 and D4:
- Plastic body on D4
- No electronic compass (D6 only)
- Weight : 85g/3.0 oz (D6: 113g/3.98 oz)
- Oxygen %: 21-50% (21-99% on D6)
- Oxygen partial pressure display: 0.5-1.6 bar (0.2-3 bar on D6)
- Recording interval: new free dive mode (default 1 second, adjustable 1, 2, 5s)
- Higher memory capacity : 80 hours of diving (D6: 36 hours), with 20 second recording interval d'intervale) contre 36 heures
- Battery life is shorter on D4 : 0 dives/y –> 2 years, 100 dives/year –>1,5 years, 300 dives/year –>1 year (D6: 0 dives/y - 3 years, 100 dives/year – 2 years, 300 dives/year – 1.5 years)
Besides the above differences, other technical specifications are pretty much the same between D4 and D6.
Alphazo