The first time that I ever saw that in person was when a seldom used roll-up shop door got used. Impressive, even after the 15' drop onto concrete.
Keith
I'm currently in the process of going through existing optics several weeks after two cataracts procedures. I tell folks that it's like getting a new lease on life.
YMMV,
Keith
I didn't watch that particular video, but the guy normally runs a Labradar for velocity testing plus he has a Chrony in front of the gel contraption.
Keith