I had a set of these in the 90's till I wore them plum out.  I didn't use them to blouse my boots though.  I tuck my pants legs in my boots and then lace them up.  When I back pack in Texas cat claw and river forging I ain't trusting some rubber band to keep out the critters and thorns out my boots.  What I use these things for is to keep my boot laces from dangling and gittin hung up on all the cat claw and stuff, coming untied and tripping me up.  Got some more now.  Thanks