SA-001SB Slide-away/Hidden shelf with a black top is 18"x6"x6" with a concealed inner shelf that is 12"x5.25"x1.75". Bolts tighten down to provide security. This is a unique 'in-house' design by staff engineers. It is one of our new 'second-amendment' shelf designs. This shelf is built to last a lifetime with expert craftsmanship by US workers.