Insulation blanket density

[RicharfPF]

I have access to 30mm thick 64kg/m3 density.insulation blanket. However i see others insulate with 96 or 128 density.
is the 64 sufficient or not? Is there much difference.
im happy to be educated.

thanks

[UtahBeehiver]

What is the thermal K rating? This is the rating that indicates how much thermal transfer occurs, the lower the value the better the insulation quality is. Also, some insulations are more prone to absorbing water than others, ie Rockwool is one.