Chainmaille VS Chainmail
What is the difference?
In short, there is no difference between the two. Chainmaille is an old English way of spelling the craft. The process of linking metal rings together can be referred by both spellings.
I use the old English spelling mostly because chain mail is something completely different and I tend not to forward emails to 10 of my closest friends.
European 4 in 1 (E4n1)
Rings can be put together in several different ways. These patterns are called weaves. European 4 in 1 is a base weave. 4-in-1 simply means that every ring in the pattern goes through 4 other rings. As a base weave there are many variations that are extremely similar or build off of the base weave. For example: Box Weave, Round Weave, E6n1, or Kingsmaille are all minor variants of E4n1. The European category is also the historical foundation for chainmaille armor whether in butted rings or flat riveted. European patterns are the basis for a wide range of items: from armor to shirts, coifs or bracers.
Half Persian 3 in 1 (HP3)
A weave that is commonly used in the stretchy bracelets that are in this store.