# How to use a boro AIO, step by step > How to use a boro AIO, from building the bridge to the first setting, with the Cthulhu AIO 2 as a worked example and the steps leaflets leave out. A tank that vanishes inside the body, a nut on top, a window down the side and no clearomiser screwed on anywhere. A **boro AIO** can puzzle at first sight, because it packs into one shell what other devices stack on top of each other. The question is which order it goes together in. Here is the sequence, from the bridge to the first puff, with a recent model as the thread running through. ## What a boro AIO is and how to use it in six steps A **boro AIO**, short for all-in-one, houses the battery, the chip and the tank in a single body. On boro models, the removable tank is called a boro tank, a format inherited from the Billet Box according to Vaping Post's review, and inside it sits a rebuildable atomiser known as a bridge. Setting one up usually follows this order. 1. Charge the cell, or slide it in already charged, positive end the right way round. 2. Build and wick the bridge, then seat it in the boro tank. 3. Pick the airflow pin that suits the draw you want. 4. Fill the tank, then slide it into the device. 5. Screw down the drip tip nut, which locks the tank in place. 6. Switch on, check the resistance reading, then set the power from the bottom up. Step 5 deserves the most attention. On this format the nut does more than hold the tank, it also carries the electrical contact between the device and the atomiser. ## The parts of a boro AIO and what each one does The format has its own vocabulary, and every part can be bought separately. The Cthulhu AIO 2, whose maker publishes a detailed product page, is a handy way to put a name to each piece. ### The device and its chip The body takes an 18650 cell and a regulated 60 W chip, the ATOM 60W V2, offering variable wattage, variable voltage, temperature control and a bypass mode. The maker placed the cell and the chip on the side opposite the tank to limit any liquid getting in. ### The boro tank This is the removable reservoir that slots into the body. The one supplied with the Cthulhu AIO 2 is made of PCTG, and the maker states it is compatible with every standard boro bridge. ### The bridge The bridge is the rebuildable atomiser that sits inside the boro tank. The TREE RBA bundled with the Cthulhu AIO 2 comes with seven airflow pins from 1.0 to 3.4 mm, for direct-lung or restricted direct-lung vaping. ### The nut and drip tip The nut screwed on top locks everything together. Cthulhu says it takes Billet Box-style drip tips, and includes a 510 adapter that also lets you dry burn a coil directly on the device. ## Preparing the bridge before it goes into the boro AIO The bridge is prepared outside the device, flat on a clean surface. On any rebuildable, the quality of the build decides everything that follows. ### Fitting and pulsing the coil The wire is clamped onto the posts, then the coil is pulsed dry, in wattage mode, to find any hot spot. The 510 adapter of the Cthulhu AIO 2 exists for exactly that job. Once the coil glows evenly, stop and let it cool. ### Threading the cotton The cotton should pass through the coil without being forced, and its ends are trimmed to the length of the juice channels. A wick packed too tight starves the coil, while one left too loose lets liquid escape through the airflow. ### Choosing the airflow pin Small pins give a tight draw, large ones an open draw. Starting with a middle size and adjusting after a few puffs works better than opening fully from the start. ## Filling the boro tank and fitting it Filling happens with the tank out of the device and the bridge in place. A large boro tank deserves a little care at this stage. Prime the cotton with a few drops first, then fill the tank, leaving some air under the cap. The TREE RBA of the Cthulhu AIO 2 is listed at 5.5 ml in its original form. In the UK refillable tanks are capped at 2 ml, and that cap applies to the boro tank. Nicotine-containing e-liquid is also limited to 20 mg/ml, in bottles of no more than 10 ml. Slide the tank into its bay, then screw the nut down until it meets firm contact. A loose nut can show up as an unstable resistance reading on screen, or as a device that detects no atomiser at all. ## Setting the chip and taking the first puff With the tank in place, give the cotton a few minutes before firing. The screen then shows the measured resistance, which should match your build. Start in variable wattage a few watts below your target, then climb in small steps. On the Cthulhu AIO 2 the ATOM 60W V2 chip offers three power modes, two of them with a preheat function, best tried once the build has proved itself. The OLED screen and the fire button light can both be switched off to spare the cell. Temperature control and bypass are modes for experienced users. The first needs a compatible wire, the second sends raw cell voltage with no regulation at all. ## Looking after a boro AIO between refills The bridge comes apart and rinses like any rebuildable, cotton removed first. The part-by-part method in our guide on [how to clean a vape](/uk/how-to-clean-a-vape/) applies to the boro tank and the drip tip alike. On the power side, a device with a removable cell can also be charged outside it, following the precautions in our [vape battery charger](/uk/vape-battery-charger/) walkthrough. Cthulhu also builds the format around a 21700 cell, the Hastur, and the fitting steps for a [21700 battery](/uk/21700-battery/) then apply unchanged. ## FAQ Questions that come up once the device is built, from the first fill to the first strip-down. ### How do you change liquid in the boro tank? Unscrew the nut, take the tank out, empty it, then remove the cotton from the bridge. Rinse the tank and the bridge, let them dry, fit a fresh wick and pick the build up again at the priming step. ### What if liquid comes out through the airflow? Check the wick first, since a wick left too loose lets liquid through. A tank filled with no air left under the cap, or a bridge not fully seated in the boro tank, can do the same. ### In what order should the device be stripped for cleaning? In the reverse order of assembly. Nut and drip tip first, then the tank, then the bridge, and the cell last if the device needs to air-dry. ### Why does the device not detect the atomiser? Two causes usually come up, a nut that is not tight enough or a dirty bridge contact. On the Cthulhu AIO 2 the maker fits an adjustable positive pin, which can take up a small amount of play. ### How long should you wait before the first puff? A few minutes after filling, long enough for the cotton to soak through to the centre of the coil. The first puff is then taken a few watts below the target, before climbing in steps. ## Getting a boro AIO off to a clean start On this format, everything else depends on three moves. Build and prime the bridge outside the device, tighten the nut until it meets firm contact, and set the power from the bottom up. Put together in that order, a **boro AIO** turns out simpler than it looks, every part being replaceable on its own. The same methodical logic applies to any rebuildable kit, whatever the shape of its shell. Editorial content for adult readers only. Nicotine is highly addictive. Vaping products are not for sale to anyone under 18 in the UK. This article is not a buying recommendation.