The 17-38 S-Test is a new test method developed in 2018 as an alternative to the CMT test. The new method was developed to measure the compressive strength of the flute/medium. A 15 mm wide specimen of uncorrugated medium is placed between two clamps. The span between the clamps is 4mm and the clamps have an offset of 1mm. The offset of 1mm compresses the flute to form an “S” shape during the test. The test result is the maximum compressive force. The S-Test can be correlated to the first plateau of the CMT.