SanDisk 128GB Ultra microSDXC Card

A1 App Performance

Android Apps Run Smoothly from the Card

The A1 (Application Performance Class 1) rating is an SD Association standard that defines minimum random read and write performance for running Android applications from a memory card. The minimum specification is 1500 IOPS random read and 500 IOPS random write — IOPS being input/output operations per second, the metric that governs how quickly an app can load its scattered small files from storage. The rating matters because Android apps are not stored as single large files — they consist of thousands of small files accessed in non-sequential patterns. Sequential read speed (the megabytes-per-second figure on the packaging) measures how fast a single continuous stream of data is read, which is relevant for video playback and file transfers. Random IOPS determines how quickly the card handles the small, scattered reads that running an app requires. A memory card without A1 rating may have adequate sequential speed but poor random performance, causing noticeable lag when opening and using apps stored on it. The SanDisk Ultra’s A1 rating ensures it meets the minimum threshold for acceptable Android app performance when used as expanded app storage on compatible devices.

140MB/s Read · UHS-I

Fast Transfers · Full HD Ready

The 140MB/s sequential read speed is achieved via UHS-I (Ultra High Speed bus I), the interface used by the majority of consumer smartphones, tablets, cameras and card readers. UHS-I provides a maximum theoretical bus speed of 104MB/s in SDR104 mode — SanDisk’s proprietary interface optimisation pushes the Ultra card beyond this to 140MB/s on compatible readers. The practical impact of 140MB/s vs the older 100MB/s versions is felt when moving large numbers of photos or long videos from the card to a computer: a 10GB video file copies in approximately 67 seconds at 140MB/s compared to 100 seconds at 100MB/s. For video recording, the Class 10 / U1 rating guarantees a minimum sustained write speed of 10MB/s — sufficient for continuous Full HD 1080p recording at standard bitrates used by smartphones and action cameras. This rating is not sufficient for 4K video recording at high bitrates, for which U3/V30 rated cards (found in the SanDisk Extreme range) are required. For Full HD recording in smartphones, dashcams and mid-range action cameras, the Ultra’s Class 10 / U1 specification is appropriate.

Durability · SD Adapter

4-Proof · Versatile Use

The SanDisk Ultra microSD card is rated waterproof (IPX7 — submersible to 1 metre for 30 minutes), temperature-proof (tested across the range from -25°C to 85°C, covering storage in a car glove box in summer heat or winter cold), shockproof (withstands drops onto hard surfaces without data loss) and X-ray proof (passes through airport security X-ray machines without affecting stored data). These ratings reflect the card’s suitability for everyday carry in a phone or wallet card slot, where incidental exposure to rain, heat, drops and travel is routine. The included full-size SD adapter provides a simple way to use the microSD card in any device or card reader with a standard SD slot — cameras that use full-size SD cards, laptop SD card readers and USB card readers all accept the adapter. This makes the card directly usable for transferring content between a phone and a camera or computer without requiring a dedicated microSD reader. The 10-year limited warranty from SanDisk covers manufacturing defects for the working life of most devices the card will be used in.

Great choice if you…

✔ Need extra storage for an Android phone, tablet or Nintendo Switch
✔ Record Full HD video with a smartphone, dashcam or action camera
✔ Want an A1-rated card for running Android apps from external storage
✔ Want reliable everyday carry durability — waterproof, shockproof, temperature-proof
✔ Need an SD adapter included to also use the card in cameras or laptops

Consider something else if…

✖ You record 4K video — the Ultra is Class 10/U1; 4K requires U3/V30; see SanDisk Extreme
✖ You use a mirrorless or DSLR camera with burst RAW shooting — see SanDisk Extreme Pro
✖ You need faster app performance — A2-rated cards offer higher IOPS for demanding apps

Technical Specifications

Box Contents

Condition

Brand New — Retail Packaging

Warranty

10 Years SanDisk (limited)

Delivery

4–5 Working Days · Fully Tracked