Bloomers are an undergarment like item used for modesty (and go over your usual underwear!). As skirts can be a bit on the short side or poof from the petticoats combined with the wind can lift the skirts up, it stops your underwear from being shown. Usually an essential staple of a lolita wardrobe, but can easily be done without or supplimented with other like garments. Bloomers can be the length of short shorts, or go as long as the knees. Some people like to show off the bottom of their bloomers, which can have ruffles or patterns or bows.
Bloomers can come in any color you might find in a Lolita outfit, but are genreally sold in white, offwhite, or black and are intended to match your petticoat.
Bloomers lengths can vary from very short to just below the knee and may feature ruffles all over, ruffles just on the back, attached petticoats, or even attached garters.
Bloomers can be considered as an "extra" on lolita outfits (specially in hot weather); however, they are strongly recommended. For those who aren´t comfortable wearing bloomers or can´t wear them for any reason, running shorts can be an option.