Yes, the pouches in these units are Perflex, which lasts several
years and then fails all at once.  I have restored a few of these.
They require chrome-tanned leather replacements.

The pouches are held down with PVC rings pressed into milled aluminum
holes.  They are fairly straightforward to replace.  The valves usually
need nothing.

D. L. Bullock    Piano World    St. Louis

 [ I remember Don Barr, president of Universal Piano Co., saying in
 [ 1978, "Robbie, this is the same material which condoms are made
 [ of: it'll never rupture and it'll last almost forever..."
 [ -- Robbie  :-(