Holt Allen's Sliding Gooseneck - Square Base 8mm Groove has an 7/16 in. (11mm) wide x 13/32 in. (10mm) thick backing plate that is snugged with a rotating knob, which is below the gooseneck pin. It the slider fits into a 5/16 in. (8mm) groove. Holt also makes a sliding gooseneck that fits an 8mm mast groove (HA41141).
|Note||Backing plate width: 16mm|
|Additional Notes||Backing plate thickness: 6 mm|
|Pin/Hole Diameter (mm)||12|