In article , "Bushy"
writes:

Substitute pitot tube cover:

Brightly coloured squeaky dog toy. Once your dog chews a hole in it and the
squeaker won't work unless you hold your finger over it to confuse your poor
puppy, then you can use it knowing that it will be visible and remembered
during preflight.

I use an old tennis ball. Cut a slit in the ball and squeeze the ball to open
the slit to make it easy to put on. Also two balls to cover the vents.
Attach a foot long piece of red spinnaker cloth to each.

Chuck