Overview
The Yocan UNI Pro 2.0 and Vessel Compass both sit in the $35 to $45 range for 510 batteries, but they couldn't be more different in what they prioritize. The UNI Pro 2.0 gives you an OLED screen, 0.1V voltage precision, and a 650mAh battery for $34.99. The Compass gives you premium anodized aluminum, full cartridge enclosure, and some of the best airflow in the category for $45.
The Compass launched first in June 2020 (per Vessel's Shopify store). The UNI Pro 2.0 came later in January 2022 (per Yocan's store). The Yocan is the newer device by about 18 months, and it shows in features like the OLED screen and 0.1V precision that the Compass doesn't have.
This is a classic features-vs-build debate. The Yocan packs in everything a power user could want at a lower price. The Vessel strips features back and puts the money into materials and engineering. We've spent weeks with both to figure out which approach actually wins.
Build & Design
Pick these two up and the Compass feels like the more expensive device. The anodized aluminum body has a quality that the UNI Pro 2.0's zinc alloy doesn't quite match. Vessel clearly spent money on materials, and you can feel it in your hand. The compact, rounded shape looks good too. It's one of the better-looking batteries you can buy.
That said, the Compass has a real problem: it's slippery. The smooth aluminum finish offers almost no grip, and the device can't stand upright on its own. There's no lanyard hole either. If you set it on a slightly angled surface, it's going to slide. Some users have reported cracking cartridges from drops caused by the slick body, which is ironic for a device built around cart protection. Vessel addressed this with the newer Compass Rise (around $60), but the original Compass still has this issue.
The UNI Pro 2.0 isn't winning any beauty contests, but it's practical. The boxy shape sits flat on any surface. The zinc alloy body has survived drops on pavement and even accidental water exposure according to long-term users. It feels like a tool built to take abuse, not a fashion accessory.
The Yocan also has the OLED screen, which is a genuine advantage over the Compass's 3 LED indicators. You can see your exact voltage, puff count, and battery percentage at a glance. The Compass's LEDs are dim, and some users struggle to tell whether the device is even on in bright light. When you're dialing in a new cartridge, knowing you're at exactly 2.8V versus somewhere between the second and third LED preset matters.
Cartridge Compatibility & Protection
Cart protection is the Compass's strongest selling point. Your cartridge drops fully into the body and stays enclosed on all sides. No exposed glass, no risk of snapping the mouthpiece off in your pocket. If you've ever cracked a cart on a standard stick battery, you understand why this matters.
The UNI Pro 2.0 takes a different approach. The adjustable width dial and height mechanism let you fit virtually any 510 cartridge, from skinny CCELL rounds to fat full-gram tanks. Your cart sits inside a chamber that provides partial protection, with an oil viewing window so you can check your levels. It's not full enclosure like the Compass, but between the chamber walls and the adjustable grip, your cart is decently shielded.
The Compass uses a swivel mouthpiece that folds flat for pocketing. Clever design, and it keeps the overall profile slim. The trade-off is that the fixed drop-in chamber doesn't accommodate extra-wide cartridges. If you use standard-width carts, you'll be fine. If you run chunky hardware, measure first.
For universal fit, the Yocan wins. For pure protection, the Compass wins. Both are massive upgrades over exposed stick-style batteries.
Voltage Control
This isn't close. The UNI Pro 2.0 adjusts from 2.0V to 4.2V in 0.1V increments. That's 22 distinct settings. The Compass gives you 4 presets: 2.4V, 2.8V, 3.2V, and 3.6V.
| Feature | UNI Pro 2.0 | Compass |
|---|---|---|
| Voltage Range | 2.0V - 4.2V | 2.4V - 3.6V |
| Increments | 0.1V steps | 4 fixed presets |
| Total Settings | 22 | 4 |
| Display | OLED screen | 3 LEDs |
| Preheat | Yes (10 sec) | No |
The Yocan's range also extends higher. At 4.2V, you can push through thick distillate that barely moves at lower voltages. The Compass caps at 3.6V, which handles most carts fine but leaves you stuck if you get an oil that needs more heat.
The UNI Pro 2.0's preheat function (10 seconds at your set voltage) is another feature the Compass lacks. Hit the button twice and it gently warms your oil before you draw. Useful in cold weather or with thick concentrates that need loosening up.
Full Spec Comparison
| Spec | Yocan UNI Pro 2.0 | Vessel Compass |
|---|---|---|
| Price | $34.99 | $45.00 |
| Battery | 650mAh | 550mAh |
| Voltage Range | 2.0V - 4.2V | 2.4V - 3.6V |
| Voltage Steps | 0.1V (22 settings) | 4 presets |
| Display | OLED | 3 LEDs |
| Charging | USB-C | USB-C |
| Threading | 510 (magnetic adapter) | 510 |
| Body Material | Zinc alloy | Anodized aluminum + plastic faceplate |
| Dimensions | 69 x 44 x 22mm | 2.625" x 1.625" x 0.75" |
| Weight | Not specified | 70g (2.5 oz) |
| Cart Fit | Adjustable width + height | Fixed drop-in chamber |
| Cart Protection | Partial (chamber + window) | Full enclosure |
| Preheat | Yes (10 sec) | No |
| Warranty | Standard | 6 months |
Performance & Airflow
Airflow is where the Compass punches back. Vessel engineered the air path to be open and unrestricted, and you can feel it on the first pull. Draws are smooth, natural, almost effortless. Several long-term users report getting more out of each cartridge because the consistent airflow vaporizes oil more evenly. One estimate puts it at roughly 5% more use per cart compared to tighter-draw batteries.
The UNI Pro 2.0's draw is fine. It's a normal, slightly restricted pull that most cart users are used to. You won't complain about it, but you also won't write home about it. The magnetic 510 adapter adds a tiny bit of air restriction compared to a direct-thread connection, though it's barely noticeable.
Vapor production on both is solid. The Yocan's wider voltage range lets you chase bigger clouds if that's your thing, while the Compass's airflow keeps hits smooth even at its highest 3.6V setting.
For flavor chasers, the Compass at 2.4V or 2.8V produces some impressively clean, terpy hits. That open airflow means you're tasting oil, not hot metal. The UNI Pro 2.0 at 2.0V to 2.5V competes on flavor thanks to its lower voltage floor, but the draw isn't as silky.
Battery Life
The UNI Pro 2.0 wins with 650mAh versus the Compass's 550mAh. That 100mAh gap translates to roughly a day of extra use for moderate users. Both charge via USB-C, so no digging for old cables.
Neither battery is going to last a heavy user more than a day or two. If you're taking 50+ puffs daily, you're charging both of these nightly. The Yocan just gives you a bit more runway before the OLED screen shows a low battery warning. The Compass, with its dim LEDs, might die on you without much notice.
Who Should Get the UNI Pro 2.0?
The Yocan is the better pick for most 510 battery shoppers. Get it if:
You want precise control over your sessions. 22 voltage settings and an OLED screen let you dial in every cartridge exactly. New cart? Start at 2.5V and work up until you find the sweet spot. That kind of tuning isn't possible with 4 presets.
You use different cartridge sizes. The adjustable width dial and height mechanism handle everything. You'll never buy a cart that doesn't fit.
You want more battery for less money. 650mAh and $34.99 versus 550mAh and $45. The math is simple.
You need a preheat function. Cold mornings, thick oil, stubborn carts. The 10-second preheat gets things moving.
Check our UNI Pro 2.0 review for the full breakdown, or see how it stacks up in our best 510 thread batteries roundup.
Who Should Get the Vessel Compass?
The Compass isn't the better value, but it's the better device for a specific type of user. Get it if:
Cart protection is your top priority. If you've cracked glass cartridges on exposed batteries, the full-enclosure design solves that problem completely. Nothing else in this price range protects carts as well.
Airflow matters to you. The Compass has some of the best draw quality in the category. If a restricted, tight pull bothers you, the Compass's open airflow is a genuine upgrade.
You care about aesthetics and materials. The anodized aluminum feels premium in a way that the Yocan's zinc alloy box doesn't. If your gear's look and feel matter, the Compass delivers.
You keep voltage simple. If you don't want to fuss with 22 settings and just want to pick low, medium, or high, the 4-preset system is faster and easier.
If the slippery body concerns you, look at the Compass Rise for about $60, or consider Vessel's Core for a different form factor. Read our full Compass review for more details.
The Bottom Line
The UNI Pro 2.0 gives you more of almost everything for $10 less. More voltage range, more battery capacity, more cart compatibility, more information on screen. It's the practical choice, the one that makes sense on a spreadsheet and backs it up in daily use. Yocan built a device that covers all the bases without cutting corners where it counts.
The Compass gives you better build materials, better airflow, and better cart protection. Vessel built a device that feels premium and solves the broken-cartridge problem that plagues stick batteries. It just asks you to pay more and accept fewer features for those strengths.
For most cart users, the Yocan UNI Pro 2.0 is the smarter buy. The Compass earns its place if airflow and protection matter more to you than voltage precision and screen feedback. Both are solid picks in a crowded 510 battery market. The Yocan just happens to be the one that's harder to argue against.
Already decided on the Yocan but not sure which model? See our UNI Pro 2 vs UNI 3 comparison to pick the right one.