Spring-loaded never lets go. The only smoke ejector holers that are spring loaded to prevent damage to door jambs. QUIC-GRIP brand is strong, lightweight, and easy to handle. Unique locking action exerts maximum pressure for secure holding against door jambs and window frames. It's virtually maintenance free. Rubber cushion pads tightly grip smooth surfaces, yet are easily adjusted from 29-1/2" to 42-1/2". Made of high tensile strength aluminum with manganses bronze handles and racks. Model VM-7 brackets are recommended for mounting the SEH-3 in vehicles. Also see Model SEH-HB for chrome plated hooks for permanent attachment to smoke ejector housing.