Most domestic sewing machines require the same system of needle that have a flattened top of the shank with a groove for the thread to travel to the eye. They also have a scarf on the back of the needle around the eye, these are 130/750H. There are several different categories of needles within this system, they differ in size, needle point shape, and eye.
J, MIC, SUK, L, S etc. indicate the type of fabrics (or task) these needles are intended for.
80/12, 90/14 is the diameter of the needle in two different units, mm (80 =.8mm) and a numbering system recognised in the USA and Aisa. Use these numbers as a guide to the weight of thread and fabric they are suitable to use with.
Your choice of needle is critical to the success of your project, the size and shape of the point depends on the fabric you are sewing. There is a leaflet that is very useful to help you choose. Click Here