Gropper Mfg. Co., Inc, a manufacturer in Brookly, NY, manufactured yo-yos and tops from the 1950's to 1960's. The company however, started before that in the 1920's, manufacturing a lot of toys, including construction toys. During the yo-yo manufacturing period, one yo-yo, the Gropper Up-N-Down was produced in various guises and versions.
Gropper was responsible for many toy creations in the 1920's and beyond. They were a manufacturer of some girl toy kits such as the "Practical Knitter", the "Mayflower Sewing Kit" to mention a few. Many of the toys they created are either now hoarded by serious collectors, possibly sitting treasures in an attic, or obsolete.