The inline enclosure is used when the cables needed to be spliced are in a line that is one cable end from the left and the other from the right, this will prevent the bending of the cables when performing the splice. The inline enclosure comes in various models that cater to different fiber types like loose tube or ribbon slot fiber cable and the numbers of fiber cores to be spliced. It usually comes with good ingress protection rating such as IP65 and IP68.
Dome enclosure is meant for housing and protecting the splices of fiber optic cables. It is called a dome enclosure because of its dome-like structure which is usually made with high-quality industrialized plastic material. This will help to ensure the enclosure provides the airtight and watertight environments for the fiber optic cables.