A clamp comprises a fastener, a clamp body, and a clamp leg. The clamp body comprises a housing including a cavity and a housing cavity; and a curved arm extending from the housing. The clamp leg comprises a leg body including a leg cavity, and a foot member. The clamp body and the clamp leg are attachable to and detachable from each other, and a portion of the leg body can be inserted into or removed from the housing cavity, and when the portion of the leg body is inserted into the housing cavity, the cavity and the leg cavity form a passageway for the fastener so that threads of the fastener are not externally exposed.