Are you looking for the solvy for the top (on top of the towel to keep the loops down)? If so, I use the light weight one. If for something other than as a "topper" please provide the details and I am sure someone will come along with more help soon.
Thank you pcteddyb, yes it is as you say for the top, but can I ask what would be using it
sorry hit wrong key. What would one be making to use this film underneath?