Check the listing for details. RAM-103U-B RAM Double Socket Arm with Round Ball Plate -.... Color: Black, Condition: New. Listed at 50.44 USD. RAM Double Socket Arm with Round Ball Plate -... RAM-103U-B Genuine RAM Products! The RAM-103U-B consists of the 1.5 INCHES diameter ball and socket system with one open socket end. This mount is designed to be used with any of the RAM mounting bases or cradles with a 1.5 INCHES diameter rubber ball. The round base has a 1.5 INCHES diameter rubber ball connected at right angles to a 2.5 INCHES diameter base. The plate has pre-drilled holes in the base, including the universal AMPS hole pattern.socket to socket length 2.5 INCHES hole pattern 4-Hole AMPS: 1.181 INCHES x 1.496 INCHES 3-Hole 120-Degree: 1.812 INCHES Diameterball size C Size (1.5 INCHES )weight capacity Standard Use: 4 lbsHeavy-Duty Use: 3 lbsmaterials Marine-grade aluminumpackaging type Poly BagWeight 0.65 lb socket to socket length 2.5 INCHES hole pattern 4-Hole AMPS: 1.181 INCHES x 1.496 INCHES 3-Hole 120-Degree: 1.812 INCHES Diameter ball size C Size (1.5 INCHES ) weight capacity Standard Use: 4 lbsHeavy-Duty Use: 3 lbs materials Marine-grade aluminum packaging type Poly Bag Weight 0.65 lb