We have ten, metric.

One needs to be
Royal for Imperial.

The best 5 x 5 by far.

Mechanics use feeler
gauges to gap plugs
and points.

Fingers are feelers
too, plus, they have
corrugated tops for
extra sensation.

Also, an advantage
when nose picking.

Thumb & *******
are for holding 6 packs
a metaphor for (i) and *

Then there is the pointer,
the index, the tickler!

But last of all, the ring
finger, good for nothing
but a hoop harness.