What each material actually is, and what the numbers behind a case claim mean.每一種材質究竟是什麼，以及手機殼那些宣稱背後的數字代表什麼。
A phone case is a thin-walled box that has to survive a pocket, a hand and a table. We put every candidate material through the same three questions: what is it genuinely good at, what does it cost the customer in daily use, and where does it fail? These three survived. The reasoning is written out below rather than implied.手機殼係一個薄壁盒，要捱得住口袋、手同桌面。每一種候選材料，我們都用同一三條問題去秤：佢真正擅長乜、日常使用要客人付出乜代價、佢喺邊度會失手。下面三種係過得關嘅三種，理由寫出來，唔靠暗示。
A panel resists bending in proportion to the cube of its thickness, and the stiffness of the material itself multiplies that figure. A material with a far higher modulus can therefore be much thinner and still feel rigid — which is the whole reason a 0.7 mm aramid shell feels firm where a 1.8 mm plastic one feels soft. 一塊板抗彎嘅能力同厚度嘅三次方成正比，再乘材料本身嘅模數。所以模數高得多嘅材料，可以薄好多都仍然硬淨——呢個就係 0.7 毫米芳綸殼摸落實淨、而 1.8 毫米塑膠殼摸落軟嘅全部原因。Good at: staying thin, staying light in a pocket, a dry texture that does not show fingerprints, and holding its shape for years.擅長：薄、放口袋輕、乾爽唔顯指紋、多年唔變形。 It fails in three places. 佢喺三個地方會失手。It is a tension material, so it kinks under compression instead of absorbing it. UV and moisture degrade it unless it is sealed in resin. And it does not cushion: aramid spreads an impact, which is not the same as taking one.佢係受拉材料，受壓時會扭結而唔係吸收能量；唔封樹脂，紫外線同濕氣就會降佢強度；而且佢唔緩衝——芳綸係分散衝擊，同「承受衝擊」係兩件事。
Full-grain is the outermost layer of the hide with the natural grain intact. Top-grain has been sanded smooth; bonded leather is scraps glued together. Only full-grain develops a real patina, because the oils in your hands and the light on your desk keep working on the same open surface. 頭層皮係皮料最外層，天然粒面完整；二層皮打磨過；再生皮係碎料黏合。只有頭層皮會形成真正嘅包漿，因為你手上嘅油脂同枱面嘅光，一直喺同一塊開放嘅表面上繼續作用。Good at: looking better with age, a warm grip that does not slip, and recovering from scuffs — leather can be conditioned, plastic can only be replaced.擅長：越用越靚、溫潤防滑、刮痕可以救——皮可以上油養返，塑膠只可以換。 It fails in four places. 佢喺四個地方會失手。It is maintenance, not a one-off purchase: unfed leather dries, cracks and stains. It soaks up water and oil. At 1.6–1.9 mm and 24–29 g it is neither the thinnest nor the lightest option. And no two hides are identical, so no two cases are either.佢係一件要保養嘅嘢，唔係一次性買賣——唔上油嘅皮會乾、會裂、會食色；會吸水吸油；厚 1.6–1.9 毫米、重 24–29 克，既唔係最薄亦唔係最輕；而且冇兩張皮係一樣，即係冇兩個殼係一樣。
Drop protection is not something you can name on a box. It is three decisions made together: a rigid back panel to spread the point of impact, a flexible frame with air-cushion corners to give that impact somewhere to deform, and raised lips so the glass never reaches the table. 防摔唔係一個可以寫上盒面嘅材料名，而係三個一齊做嘅決定：硬質背板分散落點、柔性邊框加氣囊護角讓衝擊有形變空間、加高邊緣令玻璃永遠唔碰桌面。Good at: the drop you did not plan for, and the most protection per dollar of the three.擅長：意料之外嘅一摔，而且係三款中每塊錢買到最多保護嘅一款。 It fails in three places. 佢喺三個地方會失手。At 2.4–2.8 mm and 32–38 g you feel it in a pocket and in one hand. It insulates the phone, because a thick case with an air gap is a jacket. And MIL-STD-810G is a target we state rather than a certificate we hold, until a laboratory puts its name to it.厚 2.4–2.8 毫米、重 32–38 克——放入口袋同單手揸都感覺到；而且佢令手機更難散熱，因為厚殼中間有空氣層，等於一件保溫衣；至於 MIL-STD-810G，係我們寫出來嘅目標，唔係我們手上嘅證書，要有實驗室署名才算數。
Aramid is a synthetic fibre with very high tensile strength and low density. Woven into a sheet and laminated with resin, it makes a case shell that is roughly half the thickness of a TPU case at similar stiffness.芳綸是一種高拉伸強度、低密度的合成纖維。織成布再與樹脂複合，在相近剛性下，殼體厚度大約是 TPU 殼的一半。
Full-grain is the outermost layer of the hide and keeps the natural grain. Top-grain is sanded smooth; bonded leather is scraps glued together. Only full-grain develops a real patina. We use full-grain, vegetable-tanned hides over a TPU frame.頭層皮是皮料最外層，保留天然粒面；二層皮經過打磨；再生皮是碎料黏合。只有頭層皮會形成真正的包漿。我們用頭層植鞣皮，內裡是 TPU 吸震框。
The usual reference is MIL-STD-810G, Method 516.6, Procedure IV: 26 drops from 1.2 m onto a hard surface, covering corners, edges and faces. A case that genuinely passes it usually has a stiff back panel, a flexible frame, and corner voids.常用參考是 MIL-STD-810G 方法 516.6 程序 IV：從 1.2 米高處跌落到硬質表面共 26 次，涵蓋角、邊、面。真正通過的殼通常有硬質背板、柔性邊框，以及角落的空腔結構。
| Design element結構 | What it does作用 | Ignore it if…什麼情況可以忽略 |
|---|---|---|
| Air-cushion corners氣囊護角 | Gives impact somewhere to deform讓衝擊有地方形變 | —— |
| Raised camera lip鏡頭加高 | Keeps the lens off flat surfaces讓鏡頭不碰平面 | You never put the phone down從不放下手機 |
| Raised screen lip屏幕加高 | Protects face-down drops保護屏幕朝下的摔落 | You use a screen protector已貼保護貼 |
| Stiff back panel硬質背板 | Spreads point impact分散點狀衝擊 | You want a flexible feel想要軟殼手感 |
MagSafe compatibility is a magnet array, not a logo. An N52 ring aligned to the coil holds accessories securely and lets charging through; a weak or misaligned ring does neither. Aramid and polycarbonate do not block the field — thick metal plates do.MagSafe 相容靠的是磁石陣列，不是一個標誌。對齊線圈的 N52 磁石環能牢固吸住配件並讓無線充電通過；磁力弱或位置偏移則兩者都做不到。芳綸與 PC 不會阻擋磁場，厚的金屬片才會。
If an “aramid” case weighs over 20 g, it is probably not aramid.「芳綸」殼如果超過 20 克，大概不是芳綸。
A caliper settles most marketing claims in ten seconds.一把卡尺十秒鐘就能驗證大部分宣傳。
Put it face-down on a table. If the glass touches, it is not protecting the screen.正面朝下放桌上。如果玻璃碰到桌面，它就沒在保護屏幕。
Any brand claiming MIL-STD-810G should be able to name the lab.任何聲稱通過 MIL-STD-810G 的品牌，都應該說得出是哪家實驗室。
Two more pages for anyone still deciding between the three materials.如果你仲喺三種材質之間揀，呢兩頁會有幫助。