DJ-1290TR Top Ring, +.005" BSP/Clone

This is a slightly oversized (file-to-fit) compression ring used in a standard bore Box Stock clone engine.  It is basically designed to close up the end gap on the compression ring since "stock" compression ring gaps are generally too wide.
Research has shown us that you want a minimum compression ring gap of .006".  Any closer and the rings will expand to close the gap completely during operation.

Top ring .057"