You have to print 2 center_parts, 2 side_parts, 1 lever_parts for one flying clamp.
Use 60% or more for fill when printing for the strength of the parts.

You need additional parts following,

1) a M6 eye-bolt (L=60mm) You can buy it from Ali-express
2) 4 6mm x 3mm neodymium magnets You can also buy it from Ali-express
3) 2 M5 bolts (L=30mm and 35 mm)
4) 2 M5 nuts and a M6 nut (lock nuts recommended)
5) Some sand paper (#200 -600)
 

See https://www.thingiverse.com/thing:3414914 for the original tennis version