when you take your instrument out of its case, never put it on the ground. Place it directly to your tripod, secure it with the mounting bolt then close the case. It is a bad habit to place your instrument on the ground for a couple of reasons, dirt gets on the bottom of the instrument which then gets on the head of the tripod and also gets into the case after the instrument is used. And the worst, the instrument may tip over if it is uneven. imagine at total station or theodolite tipping over.