Rumors of a liquid metal iPhone have been floating around for years. Now a newly published patent may reveal one way Apple could use the technology in future devices.

The patent, which was published on Tuesday and filed early last year, details how a stronger alloy manufactured by Liquidmetal Technology could be used to make the buttons for future iPhones. The material is apparently easier to mold into small, specific shapes. It’s also more durable, meaning these buttons won’t wear out as quickly.

The patent refers to a new type of “pressure sensor,” suggesting it might be focused on the Home Button. However, the same material could theoretically be used to make the power and volume buttons for future iPhones as well.

Apple already has an exclusive license on LiquidMetal’s special alloy. For the moment, it’s only used the material to build a special SIM card ejection tool, but now there’s evidence we may see the same technology included in the actual design of future iPhones.