New key membranes aren’t just for keeping typing noise to a minimum.

While Apple’s redesigned keyboards in the new MacBook Pro models are made to be quieter, they also appear to be designed to prevent another problem. According to a document sent to Apple Authorized Service Providers and obtained by MacRumors, the new keys have a “membrane” underneath that helps “prevent debris” from getting into the butterfly mechanism.

“The keyboard has a membrane under the keycaps to prevent debris from entering the butterfly mechanism,” state the Canadian and European versions of the document. “The procedure for the space bar replacement has also changed from the previous model. Repair documentation and service videos will be available when keycap parts begin shipping.”

The US version of the document doesn’t mention the membrane specifically. However, it does link to another document entitled Butterfly Mechanism Keycap Replacement MacBook Pro (2018), which references the membrane under the keycaps as a method of stopping debris from entering the keyboard.

Upon debuting the new MacBook Pro models, Apple insisted that the new keyboard was designed for a quieter typing experience and it was not designed to fix “sticky-key” issues. But iFixit hypothesized that this silicone membrane was indeed designed to stop dust and debris from getting under the keys after the site discovered the membrane during its teardown of the new 13-inch MacBook Pro.

A number of MacBook and MacBook Pro users have complained about the sticky-key problem over the past few years, which causes keys to get stuck or become unresponsive due to dirt, dust, crumbs, or other debris obstructing the butterfly mechanism. To address those complaints, Apple launched a repair program that lets users get their keyboards fixed for free.

Apple maintains that the sticky-key problem wasn’t widespread, but the company was hit with a few class-action lawsuits because of it. Admitting to fixing the problem with a keyboard redesign could hurt Apple, as it may be a sign of a larger problem.

It’s worth noting that the 2018 MacBook Pros are not included in Apple’s keyboard repair program. Also, according to MacRumors’ report, third-generation keyboards that feature this membrane will not be offered as replacements in the repair program.

Keep an eye out for Ars’ full review of the new 15-inch MacBook Pro, with hands-on detail about the new butterfly keyboard, in the coming days.