Please note: due to the design of our stands with telescopic stems, the two small grub screws at the top of the stem, may become loose over time from using the tray or head section to pull the stem up. Therefore, these stands may occasionally need some minimal maintenance by using a 2.5mm Allen key to tighten the screws. How to assemble the RATstands Z3 Tablet Stand  How to interchange the head of the RATstands Z3 Tablet Stand