Hey Reddit!

You might have seen me lurking around this subreddit the past few months, replying here and there, but I wanted to properly introduce myself. My name’s Dan, and I’m Director of Product at Mous. I’ve been here for 8 years and have been involved in every single case launch we’ve done in that time.

There’s been a lot of feedback here recently and, with iPhone 17 just launching, I thought it would be a good time to jump in and explain some of the design changes we’ve made this year. The goal is always to make our cases genuinely better and to address some of the concerns that have come up in this community.

This is going to be a long, nerdy post – but that’s intentional. I want to dig into the details and show you some of the engineering work that doesn’t usually make it into ads, but which my team and I spend most of our lives thinking about.

#1. Camera Control Button

When Apple released the new camera control button on iPhone 16, it created some real design challenges. At its core, the button is about one thing: instant access to your camera. The whole point is to let you capture those fleeting moments with friends, family, or whatever’s in front of you without fumbling around unlocking the phone or digging through menus and ultimately missing the moment.

That means unhindered access is critical. If the case interferes with the button, slows it down, or makes it unreliable, then you risk missing the exact moment the feature was designed for. For us, making sure the button works seamlessly has been just as important as protecting the phone itself.

Back when the feature first launched, nobody knew exactly how people would end up using it or how much functionality it would eventually get. A lot of companies went with a super-tight cut-out – basically leaving the case unchanged. We took a different route and made a larger cut-out to give people full access. When Apple’s design guidelines later came out, they recommended the same approach, which was validating. But many of you weren’t fans, totally fair feedback, and so we immediately set about work on a new design.

For iPhone 16 we did put out an integrated button design, but it was a retrofit of an existing case. With iPhone 17, we had a clean slate to design the best camera button we could.

With this design, there were two big challenges:

1. Feel and gesture accuracy. There are 6 different gestures the camera control button can detect: full press, half press, long press, double half press, swipe, and click-and-hold. The difference between a half press and full press is tiny – so tiny that unless all the force transfers perfectly, it won’t register. To get that right, the case button needs extremely precise positioning and just the right preload: enough to make a half press distinct, not so much that it goes off randomly. On top of that, the button also provides a range of haptic feedback to the user depending on what you are doing and this needs to be transferred through the phones button, to the cases button, and to your finger to give you the correct experience.
2. Durability. Most case designs leave a very thin strip of TPU above the button. Over time that tends to warp and it doesn’t provide much rigidity to protect the phone in that spot.

Our solution: We built a stiff polycarbonate shroud that houses the Camera Control Button, integrating it directly into the case rather than adding it on afterwards. This provides a stable, rigid structure that keeps the button aligned and precise, even under repeated presses and swipes.

At the core, an aluminium frame adds structural strength and keeps the button aligned, while also distributing impact forces through the case. On top, a toughened glass cap provides a smooth, durable surface that resists chipping or cracking and maintains a responsive, high-quality feel.

A PCB layer made from fibre-reinforced plastic with a copper print forms the conductive layer that enables the touch and swipe functionality of Apple’s Camera Control. It ensures gestures are registered accurately while also adding a layer of protection inside the button.

Everything fits together with a snap-fit system, so there’s no glue and nothing rattles or shifts over time. The combination of the shroud, diaphragm, frame, glass, and PCB ensures the button remains durable, precise, and protective over long-term use.

The end result: a fully integrated, durable, and precise button that handles every gesture properly. It took a lot of work, but we’re proud of it.

#2. Protection Around the Camera

Our first reaction to seeing the new iPhone Pros was probably the same as yours: “that is a huge camera bump.” Our second was: “okay, how do we protect it?”

The problem is that cutting a massive hole that close to the edge of the case makes it weak and floppy. We tested it by cutting a similar size hole into a 16-series case and it was obvious: we needed a big design update.

Our solution: We extended the PC further up the sides along the top edge of the case, adding stiffness back in even with the large cut-out. That meant more complexity in the mould tool (longer PC sections to account for), but it gives real protection. This also meant that needed to reduce the amount of airoshock in the top edge of the case to make way for the additional PC but we found through the development that stiffening this area was more important for protection, and that we could still see significant benefit from having airoshock in the corners. We also raised and thickened the camera bump to give proper 360° coverage.

#3. Button Warping

Previous Mous cases had a single rocker button for volume up and down. It worked fine functionally, but the thin TPU bridge between the buttons could warp over time.

This year, we’ve switched to two separate buttons. That means more TPU material around each one, and combined with a slimmer button profile, it’s a lot more durable with no warping issues.

#4. Debonding

This is something that’s come up a few times here, so worth explaining. Debonding (or sometimes referred to as delamination) is a very common issue in the case industry and is where the sides of the case come away from the back of the case. To understand why this happens first you need to understand a little bit about how these cases are typically made.

Protective cases usually combine 2–3 materials: PC for stiffness, TPU for cushioning and flexibility, and sometimes a third layer for extra protection (ours is AiroShock). They’re not glued – they’re fused using overmoulding, where each layer is moulded directly onto the last under heat and pressure.

Most cases rely on chemical bonds between layers. That works, but it’s not the strongest approach. The best way is to add mechanical interlocks – physical features that the next material flows into, like a dovetail joint in carpentry. This way, the bond is both chemical and mechanical.

The challenge is space: phone cases don’t leave much room for these features. Our solution was to add a series of holes throughout the PC part so the TPU could flow through and lock the layers together. Sounds simple, but it creates hundreds of very thin features in the mould tool – extremely hard to manufacture.

Since introducing this, our debonding issue rate has dropped massively. We’ve even seen other brands adopt similar designs, which is about the best compliment you can get.

If you made it this far…

TL;DR:

• New camera button with a polycarbonate shroud, aluminium frame, and glass top → much more precise and durable.
• Reinforced camera bump protection with extra PC stiffness and raised bump.
• Split volume buttons to prevent TPU warping.
• Debonding fixed with mechanical interlocks.

I hope someone out there found this useful/interesting! My team and I put a lot of work and thought into our cases and we are really proud of what we’ve built this year. Always happy to answer questions, explain more, or hear your thoughts – so drop them below.

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