CEMCO’s Double “J” (XJ-15) Control joint relieves stresses and strains in large plaster walls and ceilings. This product has expanded flanges for proper keying and easy application. Its unique design permits the plaster to key underneath the rolled edges for added adhesion while the walls expand and contract under typical conditions. The pull tape on the joint itself permits a clean finish when removed after the finish coat. CEMCO’s Double “J” Control Joint is manufactured from 26 ga. , G60 hot-dipped galvanized steel by Niles and distributed by CEMCO. G90 is also available upon special request.