The SLIK 6503 is an Arca-Swiss compatible SLIK quick release plate for the SLIK PBH-425DS and 525DS ball heads as well as any ball head with an Arca-Swiss compatible quick release system. These plates have a built-in, collapsible key so that cameras can be attached without the use of tools. The 6503 is 4.0 inches long and has a slot so the quick release plate can be mounted as desired for balance.