Abstract: An adjustable sleeve for supporting plumbing fixtures in a high security type environment wherein the sleeve is composed of telescoping type frames which are easily adjustable to the wall thickness yet can accommodate security type devices such as reinforcing bars. The adjustable wall sleeve of this invention includes at least two frame members which telescope with respect to each other with one of the sleeve members having cutout portions to accommodate security bars normally associated with a sleeve of this type. In still an additional embodiment, a third frame member can be easily secured to the two frame members to provide for additional adjustment in the wall thickness. The frame members are readily secured to each other either by screws or welding and at the same time will accommodate various types of plumbing units which can be securely attached to them yet will provide the security needed in a high security environment such as a prison.