My turntables are positioned on top of their road cases to reach a my desired height of about 40”.The criticism about the legs sliding is accurate, but is rectified by tightening the legs into the spring-peg hole

It is a tension adjustment of a screw against the inner leg, and if properly tightened should be adequate: if not, once you determine your preferred height(s), you could drill the inner leg and use a longer screw or pin.