The fish finder mount consists of a 1.5" ball diameter bar clamp base, a 9.1" long double socket arm and a 6.25" x 2" marine electronic rectangle plate | The bar clamp base & rectangle plate are made of 6061-T6 aluminum alloy material with CNC machining and iii grade hard anodized surface. The 1.5" ball long double socket arm is made of powder-coated, 6061-T6 aluminum alloy for durability and reliability in the most hardest marine environments | The bar clamp base includes a 1.5" TPU ball and equips with four soft rubber ring inserts that provide a snug fit and protect the mounting surface.The bar clamp base fits for 1.5"(38.1mm)/1.75"(44.45mm)/1.85"(46.99mm)/2"(50.8mm)/2.1"(53.34mm) diameter round rails. An allen key is included in the package for your convenience to install | The rectangular plate includes a C size 1.5" TPU ball and contains a variety of pre-drilled holes that are compatible with several marine electronic devices, including fish finders and chartplotters | Compatible with Garmin Fish finders and GPS Chartplotters: ECHOMAP Plus 72cv 73cv, 74cv, 75cv 77cv; GPSMAP 722, 722xs, 742, 742xs; Striker Plus 5cv, 7cv, 7sv | Compatible with Lowrance Fish finders and GPS Chartplotters: HDS Carbon 7, HDS LIVE 7, Hook Reveal 7 Series, Hook Reveal 9 Serie | Compatible with Humminbird & Raymarine Fish Finders, GPS Chartplotters. (Please Note: Not compatible with the Humminbird Helix 5, Helix 7, Helix 8, Helix 9, Helix 10, Helix 12, Helix 15 and Solix 10)