Dive Rite NiTek Q Advanced Nitrox/Trimix Dive Computer (V2) - Amazon Standard 2-gas normoxic Nitrox Upgradeable to 3-gas normoxic Trimix (21%-99% O2, 0-79% He) | Upgradeable to 7-gas hypoxic Trimix (8%-99% O2, 0-92% He) | Upgradeable to custom gradient factors (included in CO8000-TMIX) | Upgradeable to include a digital compass (included in CO8000-TMIX) Optional CCR mode with fixed PO2 set-points | Buhlman ZLH16 algorithm with three preset gradient factors of 30/75, 40/100 or 75/95 Visual alarms | Pre-dive planner gives NDL for selected gases Dive logging | Imperial/Metric settings | Lithium polymer 3.7V rechargeable battery