Ruler: measure the length of objects
AR rangefinder: you can measure the distance with your cell phone
Protractor: measure the angle of the object
Decibel test: detect noise


【 Subscription 】
1. Users can unlock all functions only with a paid subscription.
2. The subscription fee will be deducted from the iTunes account when the user confirms the purchase. It can be used for a three-day free trial and can be automatically renewed for $29.99 / year.
3. Users can turn off automatic renewal 24 hours before the end of the current subscription, otherwise it will be automatically renewed.
4. The Apple ID of automatic renewal subscription will be automatically deducted from the iTunes account 24 hours before the expiration of each billing period and the corresponding validity period will be extended.
5. Users can manage the subscription service, that is, they can go to the user account to set and close the automatic subscription after purchase.

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Privacy Policy：
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