Hinged Cap Floor Sockets (right), open and closed with floor sleeve. These 3.060" ID floor sockets are required for all Spieth Anderson volleyball posts. Sockets are constructed of non-rusting, solid cast bronze with a steel floor sleeve. Sockets are installed to a depth of 9 1/2" into concrete sub floor. This substantially absorbs the stress created on the post when under tension. Hinged cap sockets are recommended for all floor types except floating floors.