Protractor° Duo is an iPhone app made by Just2us. You don't need an account, and your saved angle readings stay in the app's storage on your device.
Your measurements
The app uses the phone's hinge angle and motion sensors to display angles and adjust the measuring interface. It processes these readings on-device and doesn't upload the sensor stream.
When you tap Record, it saves the angle, date, time, and a randomly generated identifier for that reading. Your History and measurement preferences aren't sent to Just2us or shared with our other apps. Measuring doesn't require access to your camera, microphone, photos, contacts, or GPS location.
Local app activity and review prompts
Protractor keeps local launch and session statistics, a count of recorded measurements, reward points, and review-request history. These help decide when to ask for an App Store review. These local counters aren't uploaded. The app doesn't use a third-party advertising network.
Apple controls whether its review prompt appears and handles any review you submit. Protractor doesn't receive your Apple Account details or the text of your review through that prompt.
Analytics and crash reports
Starting with version 1.1, Protractor uses Google Analytics for Firebase to understand app usage and Firebase Crashlytics to find and fix crashes. Earlier versions don't include these services.
Analytics sends automatic events such as first launch, session starts, time spent using the app, and app exceptions. Reports use an app-instance identifier and information such as the app version, device type, operating system, and language. Google receives connection information, including your IP address, and may derive an approximate location from it. This doesn't use GPS.
Crashlytics sends crash stack traces, diagnostic information about the app's state, device and operating-system information, and session or installation identifiers. Reports can include Analytics events from before a crash to help us understand what happened.
We don't send your saved readings, individual measured angles, sensor stream, installed-app list, or review-prompt counters to these services. We don't set a personal user ID. Advertising identifier (IDFA) support, vendor identifier (IDFV) collection, advertising personalization, and automatic screen reporting are disabled. We send events when an angle is successfully recorded, History is opened, the local trial expires, or a purchase panel appears, and when a purchase starts or a purchase or restore returns a result. Purchase-panel events identify whether they came from Settings or the measurement limit. Result labels distinguish success, pending approval, cancellation, verification failure, no previous purchase, and errors. These events contain no angle values, saved readings, payment details, transaction identifiers, or error messages.
Google processes this information to provide Analytics and Crashlytics. See Google's privacy policy and Firebase's privacy information. Apple's device setting for sharing diagnostics with developers controls Apple's reports; it doesn't turn off these Firebase services.
Recommendations for other Just2us apps
To recommend a compatible app, Protractor checks whether known Just2us apps can be opened on your device. It remembers which of those apps are installed, were previously installed, or have been recommended. This information and a cached app catalog are kept in a shared on-device container that participating Just2us apps can access.
Recommendations also use your device's compatibility and region setting, rather than GPS location. Protractor doesn't upload the installed-app list or recommendation history. App Store links may include a campaign label identifying where the link was shown; they don't include your saved readings or a unique personal identifier.
Network requests
The app downloads Just2us configuration, the app catalog, recommendation artwork, and optional About images. These Just2us content requests don't contain your saved angles or local usage statistics. Analytics and crash reports use separate requests described above. As with any internet request, the receiving service can see your IP address and request metadata and may process operational logs to deliver and protect the service.
Support and Apple services
Contact Support opens your mail app with our address and a subject containing the app name and version. Nothing is sent automatically, and your History isn't attached. If you send an email, we receive your email address, message, and any attachments you choose to include, and use them to respond to your request.
Sharing the app sends its App Store link through a service you choose. App Store downloads, ratings, and any diagnostics you choose to share through Apple's device settings are subject to Apple's privacy practices.
Apple processes in-app payments and purchase restores. Protractor uses verified purchase information to unlock paid features; it doesn't receive your payment-card details.
Deleting your data
You can delete individual readings or all saved readings in History. This doesn't clear the separate local usage counters or review-request history. Deleting the app removes its app-specific storage; shared recommendation data may remain while other Just2us apps use the shared container. Device backups and restores are controlled by your Apple settings.
We can't retrieve or delete your on-device History remotely. To ask about information you've sent us by email, contact [email protected].
Deleting History or the app doesn't automatically delete Analytics events or crash reports already sent to Google. Those reports are retained under the services' retention settings. Contact [email protected] with questions about data held by these services.
When you visit this website
The website is separate from the app's local measurement storage. It uses Google Analytics to measure page visits, with cookies that distinguish visitors and sessions, and loads fonts from Google. Our hosting provider, Cloudflare, also processes website requests. See Google's privacy policy and Cloudflare's privacy policy for their practices. You can manage cookies in your browser.
Questions and changes
For privacy questions, email [email protected]. For app help, use [email protected]. We'll update this page if the app's data handling changes.
Last Modified on 21 October 2026