iFixit recently revealed that Apple's latest MacBook Pros include a new protective membrane under their key caps, and now the site has stress-tested the membrane it found to see whether the silicone prophylactic can keep dust out of Apple's delicate-as-its-name-implies butterfly key switch mechanism.
The teardown team first dumped particles of a “powdered paint additive” that is apparently coarser than sand into the keyboard and concluded that the membrane does actually herd the dust to the edges of the switch area, away from the vulnerable holes where the key cap clips into the switch.
The keycap-and-membrane assembly seems to form a fairly robust seal, although iFixit stress-tested the system with even more dust and found that with “aggressive typing,” particles can eventually make their way into the mechanism itself. The site didn't comment on whether the amount of dust it used to achieve this infiltration is representative of what a normal notebook keyboard might see in its lifetime.
The new key switch condom isn't perfect, though. After its initial dust dump, iFixit moved on to finer sand and found that a few grains of the beach builder can still infiltrate the mechanism and prevent the switch from operating.
For folks who might need to get inside the keyboard to blow out dust, there's good news: Apple is now using thinner key caps that are easier to remove than those on past butterfly-equipped MacBook Pros. Still, a total keyboard replacement will require technicians to replace the entire top case of the notebook itself. Hopefully this silicone membrane can stave off that repair for a long time.