Optional jigs used with the tensile tester for measuring the internal bonding resistance of paper and paperboard. The specimen with double adhesive tape is sandwiched between two 25mm-square blocks of well-polished stainless steel, and a pressure of 150kgf is applied to stick the specimen to the blocks. As in the tensile test, the lower clamp is moved downward to apply a delamination load to the paper layers. Then the blocks are fixed in the clamps of the tensile tester. Tension is applied as in the tensile test to delaminate the specimen. The load at the rupture of paper layers is recorded. In addition, the position of delaminated layers is determined and the stated of delaminated surface is observed.