It is a bullet anchor fastener. These anchors are also called as drop in anchors. These anchors are female concrete anchor. These anchors are specially designed for anchoring into concrete. These anchors are available into steel. These anchors are dropped into pre drilled hole of concrete. After that, using a setting tool anchor within the hole in the concrete should be expanded. These products are internally threaded, which allows the mounting hardware to be removed easily while leaving the anchor in place. It is also called as hammer set anchor. It is used for overhead hangers with threaded rod, handrails, shelving, light fixture ,machinery and others. It is suitable for solid bricks, light concrete hollow core concrete chambers and timbers come with internal tapering, enabling the anchor to expand and to self lock the suspension rod into position. The anchors have knurled body for improving performance.