What are the Similarity and different of Retevis RT50&RT81?

What are the Similarity and different of Retevis RT50&RT81? It is well known that there are many different types of waterproof walkie-talkies in Retevis. Analog waterproof Walkie talkie including RT47,RT48,RT6,RT87,RT29; DMR waterproof walkie talkie including RT50,RT81,RT83,RT82,RT8. We also have RT55 ip67 Marine Radio. Many of them have very good customer feedback, and they are used […]