Multi spacer is a tile spacer that have 4 different spacing 1mm, 2mm, 3mm, 5mm in one piece.
"4x" is most popular flat spacer for general use. It can be useful in corners and under first row.
"T" is used for brick pattern like subway tile as an example.
"X" is for standard cross joint.
It is designed to be easy removed after installation and its high quality material allows to use it numerous times.