GBGI Disc OpenersHEAVY DUTY CAST OPENER ASSEMBLIES FROM GBGI If youre tired of having to replace your opener assembly every season, then the heavy duty cast opener assembly by GBGI is what your farm needs. Made here in the USA, our heavy duty cast opener assembly will outlast all the other equipment you plant with thanks to its robust and impressive design. The enhanced ductile iron bearing is cast and machined in the USA, and the assembly includes a strong steel