# Button and popup

> Learn how shoppers open a size chart and switch measurement units.

Source: https://docs.tryicona.com/size-chart/storefront/  
App: Icona: Size Chart & Size Guide  
Last updated: 2026-09-07

The [Icona Size Chart block](https://docs.tryicona.com/size-chart/getting-started/enable-size-chart-block/) adds a ruler icon and a configurable label to your product pages. The default label is **Size chart**.

## Opening the chart

When a shopper clicks the button, the chart opens in a popup. They can close it by pressing Esc or clicking the backdrop outside the popup. The product page does not scroll while the popup is open.

## Switching units

If you enable [automatic unit conversion](https://docs.tryicona.com/size-chart/charts/unit-conversion/), the popup includes a unit toggle. Shoppers can switch between the base and converted measurements.

## When the button does not appear

Icona does not show the button if the chart has no content blocks or the product has no published chart assigned to it. Use the [troubleshooting checklist](https://docs.tryicona.com/size-chart/troubleshooting/chart-not-showing/) to find other common causes.