Yocan UNI 4.0
USD $49.99 USD $37.99
COMING SOON
The Yocan UNI 4.0 is the newest UNI box mod: an adjustable 510 cart battery that fits almost any cartridge, now slimmer with a color screen.
- Fits 510 carts 8–14mm wide with adjustable height and 2 magnetic adapters
- 1.8–4.2V in 0.1V steps with a 10-second preheat countdown
- 1.26″ color TFT screen: voltage, puff count and battery
- 650mAh battery, USB-C charging in about 1 hour
- Slim 28mm-wide body
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Full warranty included
Description
Yocan UNI 4.0: The Newest UNI Box Mod for 510 Carts
The Yocan UNI 4.0 is the latest version of Yocan’s best-known 510 cart battery. It keeps the UNI’s patented adjustable height slider and diameter dial, so it fits almost any 510 cartridge from 8mm to 14mm wide, and adds a 1.26-inch color TFT screen, voltage control in 0.1V steps from 1.8V to 4.2V and a 10-second preheat with a countdown, all in a slimmer 28mm-wide body.
Authorized Yocan retailer · Genuine Yocan product · Live USD price: $37.99
Price checked October 9, 2026
What Stands Out on the UNI 4.0
- Fits slim and standard carts: the diameter dial covers 8–14mm, and two magnetic adapters (long and short) handle different cart lengths.
- Precise voltage: 1.8V to 4.2V in 0.1V steps; hold + or − to scroll faster.
- Preheat countdown: double-click for 10 seconds at 1.8V to loosen thick oil, and watch it count down on screen.
- Clear color screen: shows voltage, puff count, preheat countdown and battery, then sleeps after 10 seconds to save power.
- Slim, pocketable body: 28mm wide, with a metallic, cyber-industrial look.
How to Use the Yocan UNI 4.0
- Attach an adapter: screw one of the magnetic 510 adapters onto your cart (use the long or short one to suit the cart).
- Adjust the height: press the height button and slide the holder up or down until the cart fits.
- Adjust the width: turn the dial until the cart is held snugly (8–14mm).
- Turn it on: press the power button 5 times within 2 seconds.
- Set the voltage: use + and − to pick 1.8V–4.2V. Start low for flavor.
- Preheat (optional): double-click the power button for a 10-second preheat at 1.8V; double-click again to stop early.
- Vape: press and hold the power button while you inhale (up to 15 seconds per hit).
- Charge: use a USB-C cable and a 5V/1A charger; a full charge takes about 1 hour.
Best Voltage Settings
| Voltage | Best for |
|---|---|
| 1.8–2.6V | Live resin, thin distillate and the most flavor |
| 2.7–3.3V | Everyday hits for most carts |
| 3.4–4.2V | Thick oil and bigger clouds (check your cart’s limits) |
These are starting points. Yocan’s advice: start low and turn it up until you find your balance of flavor and vapor.
Yocan UNI 4.0 vs UNI 3.0
| UNI 4.0 | UNI 3.0 | |
|---|---|---|
| Battery | 650mAh | 650mAh |
| Voltage | 1.8–4.2V in 0.1V steps | 1.8–4.2V |
| Width | 28mm | 42mm |
| Cart diameter | 8–14mm | 11–16mm |
| Screen | 1.26″ TFT with screen sleep | 1.93″ HD animated, 3 UI styles |
| Preheat | 10 s at 1.8V with countdown | 10 s at 1.8V |
| Extras | Puff-count reset | Selectable UI modes |
Per Yocan, choose the UNI 4.0 for slimmer carts, a smaller body and finer voltage control; choose a larger-screen UNI if you prefer the animated display.
UNI 4.0 Not Working? Quick Fixes
| Problem | Try this |
|---|---|
| Won’t fire | Make sure it is on (5 presses) and unplugged: vaping and preheat are disabled while charging. |
| Cart not hitting | Screw the cart fully onto the magnetic adapter, reseat it, and clean the adapter and contact with a cotton swab. |
| Cart wobbles | Re-adjust the height slider and turn the dial until it is snug; try the other adapter length. |
| Stops mid-hit | Each hit has a 15-second safety cutoff. Let go and press again. |
| Weak hits on thick oil | Use the 10-second preheat or raise the voltage a little. |
| Still not working | Submit a retailer support ticket and we will help. |
UNI 4.0 vs Other Yocan UNI Models
| UNI 4.0 | UNI Pro 2.0 | UNI 3.0 Plus | UNI Pro | |
|---|---|---|---|---|
| Price (USD) | $37.99 | $35.90 | $37.95 | $29.99 |
| Battery | 650mAh | 650mAh | 1,100mAh | 650mAh |
| Best for | Newest model, slim carts and a color screen | Precise 0.1V control at a lower price | The biggest battery in the UNI family | The original, simple UNI |
Yocan UNI 4.0 Specifications
| Spec | Yocan UNI 4.0 |
|---|---|
| Battery | 650mAh, built in |
| Voltage | 1.8–4.2V, 0.1V steps |
| Preheat | 10 seconds at 1.8V, with countdown |
| Safety cutoff | 15 seconds per hit |
| Cart fit | 8–14mm diameter dial, adjustable height (Yocan lists >42mm), long and short magnetic adapters |
| Screen | 1.26″ color TFT; sleeps after 10 seconds |
| Charging | USB-C, 5V/1A, about 1 hour |
| Auto shut-down | After 1 hour |
| Size | 28 × 40 × 75 mm |
| Connection | 510 thread (magnetic adapter) |
What’s in the Box
- 1 × Yocan UNI 4.0
- 2 × Magnetic adapters (long and short)
- 1 × USB-C charging cable
- 1 × Instruction manual
Cartridge not included.
Helpful Resources
- Shop all Yocan · All 510 thread batteries
- How to unclog a cart
- City Vaporizer: submit a retailer support ticket
- Yocan warranty form
Yocan UNI 4.0 FAQ
What is the Yocan UNI 4.0?
The Yocan UNI 4.0 is the newest UNI box mod: a 510 thread cartridge battery with an adjustable height slider and a diameter dial, so it fits almost any 510 cart from 8mm to 14mm wide. It has a 650mAh battery, voltage from 1.8V to 4.2V in 0.1V steps, a 10-second preheat and a 1.26-inch color TFT screen.
How do I use the Yocan UNI 4.0?
Screw a magnetic adapter onto your cart and drop it in, press the height button and slide the holder to fit, then turn the dial until the cart is snug. Press the power button 5 times within 2 seconds to turn it on, set the voltage with the + and − buttons, and press and hold the power button while you inhale.
How do I change the voltage on the UNI 4.0?
Press the + or − button to move in 0.1V steps between 1.8V and 4.2V. Hold the button to change it faster.
How does preheat work on the UNI 4.0?
Double-click the power button to start a 10-second preheat at 1.8V. The screen shows a countdown. Double-click again to stop it early.
What size cartridges fit the Yocan UNI 4.0?
Yocan lists a diameter range of 8mm to 14mm with the adjustment dial, plus an adjustable-height holder. Two magnetic adapters, a long one and a short one, come in the box for different cart lengths.
Yocan UNI 4.0 vs UNI 3.0: what is the difference?
Both have a 650mAh battery, a 1.8V to 4.2V range and a 15-second cutoff. The UNI 4.0 is slimmer (28mm wide versus 42mm), fits slimmer carts (8 to 14mm versus 11 to 16mm), adjusts in 0.1V steps, shows a preheat countdown and adds a puff-count reset and screen sleep. The UNI 3.0 has a larger 1.93-inch animated screen with three UI styles.
How long does the UNI 4.0 take to charge?
About 1 hour with a USB-C cable. Yocan recommends a 5V/1A charger and no fast charging. While it charges you cannot vape or preheat, but you can still change the voltage and reset the puff count.
How do I reset the puff counter?
Press and hold the power button and the − button at the same time.
Why does my UNI 4.0 stop after 15 seconds?
That is the built-in safety cutoff: each hit can last up to 15 seconds. Let go of the button and press again.
Why is my Yocan UNI 4.0 not hitting?
Make sure it is on and charged and not plugged in, since vaping is disabled while charging. Check that the cart is screwed fully onto the magnetic adapter and seated on the contact, and clean the adapter and connection with a cotton swab. If the oil is thick, use the preheat or raise the voltage slightly.
Is City Vaporizer an authorized Yocan retailer?
Yes. City Vaporizer is an authorized Yocan retailer, so your Yocan UNI 4.0 is genuine and covered by the manufacturer warranty.
