On 23 Dec, 01:14, "js.b1" wrote:

Armaflex is a preformed pipe insulation which is closed-cell.

Armaflex is also neoprene, so that the cells flex if they do happen to
be wet and frozen. Stiffer foams (PU, PIR) will tend to crumble
gradually over the years.

One of my favourite things in the workshop ever is a roll of "Armaflex
gaffer tape", 3mm sticky-backed neoprene. It makes non-slip pads under
furniture, anti-vibration handle wrappings on power tools, draught
excluders on windows, the works.