There is a pin back. You push lever up to release pin and push down on leaver to lock pin. The pin is marked Sterling Mexico.
The word Sterling is wearing off. It measures 2 1/4" long and 1 3/4" wide. The item "Vintage Sterling Silver Mexican Pin Brooch with Flower Pot Birds Green Stones" is in sale since Friday, March 1, 2019. This item is in the category "Jewelry & Watches\Vintage & Antique Jewelry\Vintage Ethnic/Regional/Tribal\Mexican, Latin American". The seller is "rosiespurse28" and is located in Whippany, New Jersey.This item can be shipped to United States, Canada, United Kingdom, Denmark, Romania, Slovakia, Bulgaria, Czech republic, Finland, Hungary, Latvia, Lithuania, Malta, Estonia, Australia, Greece, Portugal, Cyprus, Slovenia, Japan, China, Sweden, South Korea, Indonesia, Taiwan, South africa, Thailand, Belgium, France, Hong Kong, Ireland, Netherlands, Poland, Spain, Italy, Germany, Austria, Bahamas, Israel, Mexico, New Zealand, Philippines, Singapore, Norway, Saudi arabia, United arab emirates, Qatar, Kuwait, Bahrain, Croatia, Malaysia, Brazil, Chile, Colombia, Costa rica, Viet nam, Uruguay, Switzerland, Dominica, Saint lucia, Iceland, Luxembourg, Reunion.