The Flum UT Bar Pro 50K is the most interesting disposable vape we have tested at VapesOnlineShop in the past year — and that is not a small claim when you stock 30+ brands. The headline feature: two independent e-liquid tanks in one device with a switch that lets you toggle between Flavor A, Flavor B, or activate Mix Mode to blend both simultaneously. No other disposable vape on the market offers this. At $24.99 for 50,000 puffs, it also happens to be one of the cheapest 50K options available.
Here is our detailed verdict after weeks of daily use.
What We Like
The dual-flavor system actually works — and it is a game-changer. This is not a gimmick. The two tanks are genuinely independent, each with its own coil and e-liquid supply. The switch is responsive, and the transition between flavors is near-instant with minimal flavor bleed. After a few puffs of the new flavor, the old one clears out completely. We tested the Blue Razz / Lemonade combo extensively — switching between sweet berry and tart citrus mid-session without carrying two devices is exactly as convenient as it sounds.
Mix Mode creates genuinely new flavors. Activating both coils simultaneously is not just "two flavors at once" — the blended profile is often distinct from either individual flavor. Cola Ice / Cherry creates a cherry Coke that tastes surprisingly authentic. Root Soda / Vanilla produces a root beer float. Blue Razz / Lemonade in Mix Mode becomes berry lemonade. This effectively gives you three flavor experiences per dual combo: A, B, and A+B.
40 flavor options is the largest in any single Flum device. 25 dual combos plus 15 single flavors. The dual combos include pairings no competitor offers — Tobacco / Gold Tobacco for traditionalists, Cool Mint / Icy Mint for menthol purists at two intensity levels, and Strawnana / Gelato for dessert lovers. See the full flavor list.
$0.50 per 1,000 puffs is best-in-class value. At $24.99 for 50,000 puffs, the UT 50K matches the Float Mello Pro 50K for the cheapest per-puff cost in our store — and undercuts the RAZ VUE 50K by 10-15%. See our price comparison for details.
Independent tank tracking on the HD screen. The screen shows which tank is active and tracks each tank's e-liquid level separately. If one side runs out, you can continue vaping the other. This solves the main concern users have about dual-tank systems — you are never left with a dead device because one tank depleted faster.
What Could Be Better
Slightly bulkier than single-tank devices. The dual-tank architecture makes the UT 50K wider than the UT Bar Pro 25K or the Mello 20K. It is still pocket-friendly, but noticeably heavier. If you prioritize a slim, lightweight device, the UT 25K is the more compact UT option.
Mix Mode drains both tanks simultaneously. Using Mix Mode is fun, but it consumes e-liquid from both tanks at once. Heavy Mix Mode users will get significantly fewer than 50,000 total puffs. The 50K rating assumes mostly single-flavor usage. This is a fair trade-off, but worth knowing.
No Smooth/Turbo power toggle. Unlike the UT 25K (Smooth/Turbo mode) and the Mello Pro 50K (Turbo/Eco mode), the UT 50K's switch is dedicated to flavor selection (A/B/Mix), not power adjustment. You cannot control vapor intensity — it runs at a fixed output. For most users this is fine, but power mode enthusiasts may miss the option.
Screen is HD but not animated. The Mello 20K's Mega HD Animated Screen is more visually engaging. The UT 50K's screen is functional and clear but not as flashy. Minor point, but worth noting if screen aesthetics matter to you.
How It Compares
| Feature | Flum UT 50K | Mello Pro 50K | RAZ VUE 50K |
|---|---|---|---|
| Dual Flavor Switch | ✅ Only one on market | — | — |
| Flavor Count | 40 | 10 | 50+ |
| Power Modes | Fixed (flavor switch only) | Turbo / Eco | — |
| Price | $24.99 | $24.99 | ~$27-29 |
| VOS Rating | 9.0/10 | 8.5/10 | 8.8/10 |
The Verdict
The UT Bar Pro 50K earns our highest rating in the Flum lineup because it does something no other device does — and does it well. The dual-flavor system is not a novelty; it solves a real problem for vapers who regularly switch flavors. Combined with 40 flavor options and best-in-class per-puff pricing, it is the most feature-rich Flum device at any price point. The only reasons to choose something else: you want power mode adjustability (get the Mello Pro 50K), you want the most compact option (get the UT 25K), or you want 50+ flavors from a single device (get the RAZ VUE 50K).
FAQ
Is the UT Bar Pro 50K the best Flum vape?
For features and value, yes — it has the highest VOS rating (9.0/10) in the Flum lineup. The dual-flavor switching is unique in the market, it offers the most flavors (40), and the $0.50/1K puffs is tied for cheapest. The Mello 20K beats it on flavor creativity (themed editions), and the Mello Pro 50K offers Turbo/Eco power modes it lacks.
How many puffs do you actually get from the UT 50K?
The 50,000-puff count is the combined capacity of both tanks using single-flavor mode. In our testing, we typically got 40,000–50,000 puffs with mostly single-flavor usage. Heavy Mix Mode users should expect 25,000–35,000 total puffs since it consumes from both tanks simultaneously.