Possible military unit pin

The pin is about 1 1/4" high and about 1" wide. It has depicted a palm tree, a cactus and another object surrounded by what looks like 5 stars . Its shaped like a shield, white porcelain background. At the bottom of the pin are the words " Ever Ready"
I received this and other pins from the estate of an uncle that died. He was a WWI veteran, wondering if this had a military connection.