Mares Horizon Dive Computer: Specifications and Who It Suits
The Mares Horizon is a expert tier dive computer at $1,100 and up, running Mares-Wienke RGBM with a full colour lcd and optional air integration. Divers running the Mares Horizon rebreather.
The Mares Horizon is a expert tier dive computer in the $1,100 and up band. Built around the Mares semi closed rebreather system rather than as a general purpose computer. It is bought as part of that system, and it makes little sense on its own.
The specifications below are the manufacturer's published figures. Where we could not confirm a figure against the maker's own documentation, the row is left out rather than guessed at, which is why some units on this site show fewer rows than others. On a page whose readers can check the work, a missing row is better than an invented one.
What are the Mares Horizon specifications?
| Specification | Horizon |
|---|---|
| Brand | Mares |
| Model | Horizon |
| Decompression model | Mares-Wienke RGBM |
| Air integration | Optional |
| Display | Full colour LCD |
| Battery | Rechargeable |
| Modes | Open circuit, semi closed rebreather |
| Trimix | Yes |
| Closed circuit | No |
| Price band | $1,100 and up |
| Tier | Expert |
Who is the Horizon for?
Divers running the Mares Horizon rebreather.
An expert tier computer buys capability at the edges: trimix, closed circuit support, multiple transmitters, or a screen legible in conditions that defeat everything else. Very little of that is touched by a recreational profile. Buying one is defensible if you are heading toward technical training or you dive in conditions where legibility is the binding constraint, and hard to justify otherwise.
Who should not buy the Horizon?
Everyone else. This is a system component, not a standalone purchase.
That is the more useful half of any specification page. Computers in this category are close enough on the things that matter, tracking depth and time and applying a model, that the deciding factor is usually a mismatch rather than a ranking: a screen you cannot read without glasses, a menu system nobody near you can teach, or a feature set aimed at diving you do not do. Compare against the alternatives at the bottom of this page before deciding.
What does Mares-Wienke RGBM actually mean on a dive?
A decompression model is a mathematical description of how quickly inert gas moves into and out of body tissue, used to calculate how long you can stay at a depth before a direct ascent stops being acceptable. Every computer runs one, they disagree with each other, and the disagreement is real rather than cosmetic.
RGBM implementations model bubble behaviour as well as dissolved gas, which in practice makes them more conservative than a comparable Buhlmann implementation, particularly across repetitive dives, short surface intervals and reverse profiles. Divers moving from a liberal model often describe an RGBM computer as pessimistic. It is not wrong, it is priced differently, and the difference can be tens of minutes of no-stop time on a repetitive afternoon dive.
Whichever model a computer runs, the rule is unchanged: your own computer supersedes any published table, two computers on the same dive can legitimately disagree, and a buddy pair runs the dive on the more conservative of the two. The algorithm comparison covers the trade in detail, and the no-decompression limits table shows how far apart published figures can be.
Does the display suit the diving you do?
The Horizon uses a full colour lcd. Display technology decides legibility more reliably than screen size does, and legibility is the specification that actually matters at depth.
A colour screen separates warnings from data by hue rather than by position, which is quicker to read when you are task loaded, and it stays legible in the low contrast blue-green light of deeper water where a segment display can wash out. The cost is battery, which is why colour units are usually rechargeable, and price.
Whatever the screen, check one thing in the shop before you buy: can you read it at arm's length without your glasses, in dim light, at a glance? Presbyopia arrives for most divers in their forties and it is the single most common reason a computer gets replaced.
How does air integration work on this unit?
Air integration is optional on the Horizon and needs a matched transmitter, such as the Shearwater Swift for Shearwater units. Transmitters do not cross brands, so this is an ecosystem decision rather than an accessory purchase, and it typically adds several hundred dollars. Our advice is to buy the computer on its own merits, dive it a season, and add the transmitter only if you find yourself missing it.
Air integration does not change how much gas you have or how fast you use it. That is your own respiratory minute volume, and it is worth knowing as a number rather than as a feeling. The SAC rate calculator works it out from one logged dive, and the gas planning calculator turns it into a reserve and a turn pressure.
How does it compare with the rest of the Mares range?
| Model | Tier | Display | Air integration | Price band |
|---|---|---|---|---|
| Puck Pro Ultra | Beginner | Segment LCD with backlight | No | $200 to $260 |
| Puck 4 | Beginner | Segment LCD with backlight | No | $280 to $340 |
| Quad | Intermediate | Large segment LCD | No | $350 to $450 |
| Smart Air | Intermediate | Segment LCD | Optional | $450 to $600 |
| Quad Ci | Intermediate | Large segment LCD | Optional | $500 to $650 |
| Genius | Expert | Full colour LCD | Optional | $750 to $900 |
Staying inside one brand has a genuine advantage that specification tables hide: the menu logic, the app and the transmitter all carry over, and a shop that services one unit usually knows the others. That matters most for air integration, where the transmitter is locked to the ecosystem.
What else should you look at in the same tier?
| Model | Brand | Algorithm | Price band |
|---|---|---|---|
| Eon Core | Suunto | Suunto Fused RGBM 2 | $650 to $800 |
| Aladin H Matrix | Scubapro | $650 to $800 | |
| Descent G2 | Garmin | Bühlmann ZHL-16C with Gradient Factors | $700 to $850 |
| Nepto | Cressi | Cressi RGBM | $700 to $900 |
| Tern TX | Shearwater Research | Bühlmann ZHL-16C with Gradient Factors | $750 to $850 |
| Ocean | Suunto | $750 to $900 |
What should you check before you buy?
- Can you read it? At arm's length, in dim light, without glasses. This is the most common reason a computer is replaced, and no specification captures it.
- Can someone near you teach it? A unit your local shop rents and services is worth more than a slightly better one nobody around you has used.
- Does the battery arrangement suit your travel? A rechargeable unit needs a charger, a cable and a plan on a liveaboard, and it has no hatch to flood.
- Is the price band real for you? This unit starts at $800 or more, and most of what that buys is capability a recreational profile never reaches.
- Are you buying capability or permission? A computer that supports trimix does not qualify you to dive it. Training comes first, always.
Related reading
Frequently asked questions
What decompression model does the Mares Horizon use?
The Horizon runs Mares-Wienke RGBM. RGBM implementations model bubble behaviour as well as dissolved gas, and in practice they tend to be more conservative than a Buhlmann implementation at default settings, particularly on repetitive and reverse profile dives. Whatever the model, your own computer supersedes any published table.
Does the Mares Horizon have air integration?
Yes, optionally. The Horizon supports a wireless tank pressure transmitter, sold separately. Transmitters do not cross brands, so buy the one matched to this unit and expect it to add several hundred dollars. Air integration is a convenience rather than a safety requirement, and a mechanical pressure gauge stays in the kit either way.
What kind of battery does the Mares Horizon use?
Rechargeable. A rechargeable battery means no hatch to flood and no o-ring to maintain, at the cost of needing a charger and a plan on a liveaboard. Charge it fully before travelling and carry the cable, because a proprietary charging clip is not something you can borrow.
Is the Mares Horizon a good choice for a new diver?
Probably not. At $1,100 and up this is an expert tier unit, and most of what you are paying for is capability a recreational profile never reaches. Everyone else. This is a system component, not a standalone purchase. A cheaper computer with a clear display teaches the same habits for a fraction of the money.
How we choose: we compare published manufacturer specifications, published training agency standards, and verified owner reviews across retailers. We do not test gear in person, and every depth rating, cylinder capacity and algorithm name quoted here is the manufacturer's published figure unless we say otherwise, so confirm it on the current spec sheet before you buy. Nothing here is dive instruction, and no calculator output on this site is a dive plan. Scuba diving carries a real risk of decompression sickness, oxygen toxicity, barotrauma and drowning. Dive within the limits of your certification, verify every plan with your own computer, and buy the training before the gear that assumes it.
Logging your own SAC rate and gas plans? The Dive Kit & Air Planning Workbook is the paid version of these pages: 8 printable worksheets you fill in with your own numbers, plus the full PDF, $29.