It's a little more money than these, but the IsoAcoustics are great. I ordered a pair for my LSR305's, but I can't open them until Christmas (a present for myself that has to go under the tree). Read up on AC -- many folks sing their praises. And the size on these is ideal for the 305's.
I have currently some acoustic foam under the 305's and they don't provide enough lift or do the speakers justice.
https://smile.amazon.com/gp/product/B008GOP79G/ref=oh_aui_detailpage_o07_s00?ie=UTF8&psc=1Regards, -dB