Fits most bookshelf speakers; Supports up to 15lbs ; Thread size: 3/8-16; Tilts +/-30deg ; Pans 180deg ; Base rotates 360deg ; Polymer-injected ball controls resonance frequencies for better sound; Stainless steel hardware provides strength & durability; Suitable for all-weather use; Ball & clamp design for greater mounting flexibility; Includes complete hardware kit; Single;