Check the listing for details. RAM-101U-271-12 RAM Round Post Clamp Mount with Round Plate.... Color: Black, Condition: New. Listed at 96.94 USD. RAM Round Post Clamp Mount with Round Plate... RAM-101U-271-12 Genuine RAM Products! The RAM-101U-271-12 consists of a double socket arm, a 2.5 INCHES diameter round base, and a clamping base compatible with rails from 1.25 INCHES and 1.875 INCHES in diameterhardware included (2) 1/4 INCHES -20 x 1.5 INCHES Machine Screws(2) 1/4 INCHES -20 Nylock Nuts(2) Rubber Capsclamp range 1.25 INCHES - 1.875 INCHES diametersocket to socket length 4.66 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 1.46 lb hardware included (2) 1/4 INCHES -20 x 1.5 INCHES Machine Screws(2) 1/4 INCHES -20 Nylock Nuts(2) Rubber Caps clamp range 1.25 INCHES - 1.875 INCHES diameter socket to socket length 4.66 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 1.46 lb