Features:    
0.8" (20mm) of sliding travel within plate to optimally balance gear.
Female 3/8"-16 !#!amp!*! 1/4"-20 threads on bottom.
Plate has 1/4"-20 !#!amp!*! 3/8"-16 mounting screws， in addition to anti-twist video register pin.
2-Stage Safety Quick Release System.

** This item is not manufactured by Manfrotto. It is 3rd party manufacture to compatible with Manfrotto.

Specifications:
Material: Aluminum
Plate: 501PL (Sliding travel of plate 0.79"/20.06mm)
Attachment: 1/4" !#!amp!*! 3/8" screws attachment type
Bottom: 3/8" female thread
Attachment 2: 1/4" female thread
Color: Black
Item size: Approx. 9 * 7.5 * 2cm/ 3.5 * 3.0 * 0.8in
Item weight: 258g / 9.1oz

Package List:
1 * 577 Rapid Connect Adapter with 501PL QR Plate