Trial Lens set or Trial Lens Kit Mainly consists of positive and negative sphere lens, positive and negative cylinder lens, prism lens and accessory lens etc. According to different usage, there're bascially 68 lens set, 90 lens set, 104 lens set, 158 lens set, 232 lens set and 266 lens set. The trial lens set normally come with a trial frame, also you are able to buy accessories lens as well as single lens replacement here.