> For the complete documentation index, see [llms.txt](https://docs.ackinacki.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.ackinacki.com/for-users/buy-sell-shell/buying-shell/exchange-eccusdc-for-shell-via-acki-nacki-wallet-android-only.md).

# Exchange eccUSDC for SHELL via Acki Nacki Wallet (Android only)

If you already have ECC USDC in your balance, you can instantly buy SHELL directly in the Acki Nacki Wallet mobile app.

## Prerequisites

* Acki Nacki Wallet app installed
* ECC USDC in your balance (minimum 1 USDC)

## Step-by-Step Guide

{% stepper %}
{% step %}

#### Open the Exchange Section

On the main wallet screen, where your balances are displayed, tap the **Exchange** button button and select **Buy and Sell SHELL**

<div><figure><img src="/files/PijRoudLPjBx1Jm6BBc0" alt=""><figcaption></figcaption></figure> <figure><img src="/files/vxYZyfIkGABNG7pEkxfO" alt=""><figcaption></figcaption></figure></div>
{% endstep %}

{% step %}

#### Select Buy

In the exchange screen, make sure the **Buy** mode is selected.

<figure><img src="/files/H4c2hZD9Jf2dJHG7kj7I" alt="" width="287"><figcaption></figcaption></figure>
{% endstep %}

{% step %}

#### Enter the USDC Amount

In the **Select amount** field, enter the amount of USDC (ecc) you want to spend on SHELL. The system will instantly show how much SHELL you'll receive.

**Input rules:**

* Whole numbers only (1, 5, 100, etc.)
* Minimum amount — 1 USDC
* Cannot exceed your ECC USDC balance

Your current USDC balance is displayed at the bottom of the screen.

**Example:** you enter 50 USDC — the system shows you'll receive 5,000 SHELL.

<figure><img src="/files/lhvvZLwUYcZeRLqDh3k6" alt="" width="285"><figcaption></figcaption></figure>
{% endstep %}

{% step %}

#### Tap "Buy SHELL"

After entering the amount, tap the **Buy SHELL** button at the bottom of the screen
{% endstep %}

{% step %}

#### Confirm the Purchase

A confirmation screen appears with the details:

<figure><img src="/files/8kMgWC4QOqGHf2n8lAvI" alt="" width="280"><figcaption></figcaption></figure>

Tap **Confirm** to proceed or **Cancel** to go back
{% endstep %}

{% step %}

#### Wait for Execution

The transaction is being processed on the blockchain.
{% endstep %}

{% step %}

#### Purchase Complete

On success, you'll see the confirmation:

<div><figure><img src="/files/vDCrBWzl5YA0MsD3HnYa" alt="" width="278"><figcaption></figcaption></figure> <figure><img src="/files/ymnmdw7HuN6tfDYX2uZl" alt="" width="287"><figcaption></figcaption></figure></div>

Tap **Close** to return to the main screen. Your SHELL balance will update automatically.
{% endstep %}
{% endstepper %}

## What Happens Under the Hood

When you buy SHELL, the system follows this algorithm:

1. Your USDC is sent to the Accumulator smart contract
2. The contract checks if there is SHELL available in seller queues
3. If sellers exist — their SHELL is transferred to you, and USDC is reserved for seller payouts
4. If there aren't enough sellers — the missing SHELL is created (minted) by the system
5. All SHELL is sent to you in a single transaction

As a buyer, it doesn't matter where the SHELL came from — you always receive exactly **amount × 100 SHELL**.

## Possible Errors

| Message                       | Cause                         | Solution                                 |
| ----------------------------- | ----------------------------- | ---------------------------------------- |
| Buy SHELL button inactive     | Amount field is empty or zero | Enter an amount greater than 0           |
| Enter a whole number          | A decimal number was entered  | Enter a whole number                     |
| Insufficient USDC ecc balance | Not enough USDC ecc           | Reduce the amount or top up your balance |
| Transaction failed. Try again | Transaction error             | Try again after a few seconds            |