I purchased this product after using the Medela handsfree halter and this is far more superior. It is heavyweight fabric so it does not stretch out. The double slot system helps keep the flange from sagging. Once you place your nipple in the flange you do not have to worry about readjust it. The flange stays in the same spot you left it. Once you start pumping there is no need to hold the parts at all.
The ability to make it tighter using the Velcro is wonderful. I am a 36G or 38H so that put me in both size ranges (weird I know) I went ahead and bought both but as I figured the larger one was what I needed.