Abstract: This invention relates to a retractable bollard including an embedded outer housing having an open end and a closed end; a ram slideably mounted within the outer housing; and means for injecting fluid into, and means for removing fluid from, a chamber within the retractable bollard to move the ram relative to the outer housing between a retracted position and an extended position. The chamber is bounded by one or more sliding surfaces and one or more seals configured to move in sealing relationship relative to the sliding surfaces and the ram is able to be completely removed from the outer housing without separating the seals from the sliding surfaces.

Abstract: A bollard apparatus (100) has a housing (1) and a barrier member (2) disposed at least partially within the housing (1). The barrier member (2) is slidable relative to the housing (1) between a first, extended position, and a second, retracted position. The apparatus (100) has an electrical connection means (10), at least one electrically actuable locking means (4) and an electrical path between the electrical connection means and the electrically actuable locking means. The electrically actuable locking means (4) is operable to prevent relative movement between the barrier member (2) and the housing (1) when the barrier member (2) is in at least one of the first and second positions. A system comprising the bollard apparatus (100) and an unlocking means (20) is also described.