SFF Optical Transceiver, Small Form Factor Transceiver
A small form factor (SFF) is a computer form factor designed to minimize the volume and footprint of a desktop computer. For comparison purposes, the size of an SFF case is usually measured in litres. SFFs are available in a variety of sizes and shapes, including shoeboxes, cubes, and book-sized PCs. Their smaller and often lighter construction has made them popular as home theater PCs and as gaming computers for attending LAN parties. Manufacturers also emphasize the aesthetic and ergonomic design of SFFs since users are more likely to place them on top of a desk or carry them around. Advancements in component technology together with reductions in size means a powerful computer is no longer restricted to the huge towers of old.
Small form factors do not include computing devices that have traditionally been small, such as embedded or mobilesystems. However, "small form factor" lacks a normative definition and is consequently open to interpretation and misuse. Manufacturers often provide definitions that serve the interests of their products. According to marketing strategy, one manufacturer may decide to mark their product as "small form factor", while other manufacturers are using different marketing name (such as "Minitower", "Microtower" or "Desktop") for personal computers of similar or even smaller footprint.