# DUO LINK 4 > File management and transfer app for iOS devices and OTG USB drives. (iPhone/iPad app by PNY.) - Source: https://appshunter.io/ios/app/duo-link-4/id1103672387 (this page in markdown: same URL + `.md`) - Developer: [PNY](https://appshunter.io/developer/1103672386) - Category: Lifestyle - Price: Free - Rating: 2.10/5 from 498 App Store ratings Β· 110 written reviews indexed - Age rating: 4+ - Requires: iOS 11.0 Β· 123 MB - Languages: American English, French (France), Polish, European Portuguese, European Spanish, Chinese (Traditional, Taiwan) - Released: 2016-05-31 - Data updated: 2026-08-29 - Monetization: free - User reviews in markdown: https://appshunter.io/ios/app/duo-link-4/id1103672387/reviews.md ## What is DUO LINK 4? PNY DUO LINK 4 app, designed to work with DUO LINK OTG USB 3.0 Flash Drive brings you the ability to do more when it comes to file transfer, saving, sharing, accessing and streaming. Simply connect the DUO LINK OTG USB 3.0 Flash Drive to your iPhone and iPad and start syncing, transferring, sharing files, photos, videos and more with ease. DUO LINK OTG USB 3.0 is a flash drive designed for iPhone and iPad that enables you to free up space on your iOS device, save and protrect your contents into DUO LINK and even transfer then to your computer. DUO LINK OTG USB 3.0 also provides the ability for you to charge your iPhone and iPad. Features and Benefits: - Free up space on your iPhone or iPad. - Charge your iOS device. - Back-up your contacts. - Transfer and share your videos, photos and more. - Store photos directly into DUO LINK and save space on your iPhone or iPad. - Manage files on your iPhone, iPad and on DUO LINK. - Supports independent music and video playback. - Automatically back up your photos and videos so that you don't have to. Support: Please visit PNY Support at www.pny.com/support/technical-support Supported file formats: - video: M4V/MP4/MOV - Audio: M4A, CAF, AIFF, ASF, AAC, mp3, wav - Picture: TIFF, JPEG,JPG,PNG,GIF,BMP - Document: DOC, DOCX, PAGES, RTF, TXT , PPT, PPTX, PDF, XLS, XLSX, NUMBERS, KEY, HTML PNY takes no responsibility or liability with respect to the download or usage of DUO-LINK 4 app. By downloading this app you agree to the end user license agreement from PNY, also available at http://www.pny.com/File%20Library/Unassigned/PNY--On-the-Go-End-User-License-Agreement.pdf . ## Key features - Free up iPhone/iPad space - Charge iOS devices - Back up contacts - Transfer photos and videos - Store photos directly - Manage files - Music and video playback ## What do users think of DUO LINK 4? Overall sentiment: negative **Pros** - πŸš€ Efficient file transfer - πŸ’‘ Useful for freeing up phone storage - πŸ‘ Straightforward to use **Cons** - πŸ› Frequent app crashes - πŸ” Confusing or limited UI - πŸ”Œ Compatibility issues with newer devices - πŸ’Ύ Data loss or corruption **Commonly reported bugs** - App fails to detect connected device - Transferred files not visible or accessible - Inconsistent behavior when renaming folders **Most requested features** - Add 'select all' option for photos/files - Support for more file formats - Improve iPad app experience - Integrate with native Files app ## Recent user reviews (10 of 110) All indexed reviews: https://appshunter.io/ios/app/duo-link-4/id1103672387/reviews.md ### 1/5 β€” This app suck! *2026-07-12, version 1.0.86* I now understand why there are so many low reviews: the app is difficult to use for transferring information to a thumb drive. I spent hours trying to figure it out without success. ### 1/5 β€” PNY should be ashamed *2026-05-19, version 1.0.86* I have several PNY hardware devices which have been reliable and well designed. I bought the PNY duolink usb expecting similar results. The usb is fine but to use the usb it is all about the SOFTWARE that works with iPhone. PNY should be ashamed to have such a poor and buggy software associated with their products. Appears they outsourced the software to sell usb hardware and now have a pile of garbage the consumer is left to deal with. DO NOT BUY PNY DUOLINK USB DRIVES - you will regret it ### 2/5 β€” Update the app! *2026-03-09, version 1.0.86* This works if you have the lightning version, but if you try to use the USB-C version it doesn’t. Other companies have similar apps that work for the USB-C as well so I wish y’all would pay attention & do the same. Tech support hasn’t really been helpful other than telling me to manually move them over, but even then if I select all I can’t unless I do them in multiple small batches which is time consuming. ### 1/5 β€” Worthless *2025-10-04, version 1.0.86* Don’t even waste your money ### 1/5 β€” Constant Crashing *2025-09-30, version 1.0.86* Appears to read the usb drive and when the progress bar reaches the end, CRASHES! Useless :( ### 1/5 β€” PNY/DUO LINK *2025-08-26, version 1.0.86* The flash drive and app worked well in the beginning and now the app is not reading what I saved on the flash drive. All the pics I saved are not showing. So frustrating and upsetting if I lost my pictures. ### 2/5 β€” Great device, but the app... *2025-08-05, version 1.0.86* I was checking my storage and this app takes up 45GB of space on my phone. If the purpose of the USB drive is to reduce phone storage, why does the app take so much? ### 3/5 β€” Picture in Picture *2025-06-27, version 1.0.86* Please update the app and add Picture in Picture. Please fix this app ### 1/5 β€” First impression *2025-04-03, version 1.0.86* Takes forever to load. I am in a hurry and will try again later. The device has been plugged in and the screen has not changed and still instructs me to plug in the device. I’m starting to think I bought a dud. ### 2/5 β€” it was working great but... *2025-02-08, version 1.0.86* Once this clever gizmo got full, I couldn't empty it! Even after I deleted everything on it, it still says it's full. I might have deleted the files incorrectly using my laptop or something like that but I can't find any way to reset or reformat it-- and when I try and copy files onto it, it acts like their copied but then there is nothing there. Help!?! ## Frequently asked questions about DUO LINK 4 ### What does the DUO LINK 4 app do? The app allows you to manage and transfer files between your iPhone or iPad and a compatible PNY DUO LINK OTG USB 3.0 Flash Drive. You can free up space on your device, back up important data like photos and videos, and even charge your iOS device. ### What are the key features of this app? Key features include freeing up space on your iPhone or iPad, charging your iOS device, backing up contacts, transferring and sharing videos and photos, storing photos directly to the flash drive, managing files on both your device and the drive, and supporting independent music and video playback. ### Is this app free to use? Yes, the application is available for free. There are no mentioned in-app purchases or subscription fees associated with its use. ### What devices is this app compatible with? This app is designed to work with iPhones and iPads. It requires a PNY DUO LINK OTG USB 3.0 Flash Drive to function. ### What are common use cases for the DUO LINK 4 app? Common use cases include freeing up storage space on your iPhone or iPad when it's full, creating backups of your photos, videos, and contacts, and easily transferring large files between your iOS device and a computer via the USB drive. ## Version history (last 5 releases) ### 1.0.86 β€” 2023-12-14 1.Fix known issues. 2.Application optimization. ### 1.0.84 β€” 2023-03-13 1.Fix known issues. 2.Application optimization. ### 1.0.82 β€” 2020-10-10 1.Client functional optimization. ### 1.0.80 β€” 2020-07-15 1.Compatible with ios13. ### 1.0.74 β€” 2018-12-23 1.Update tips & APP user manual for Trad. 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User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-29.*