I use the Garmin Premium HRM with the soft strap. I fully wet the strap under the tap or with a water bottle before I put it on. It works every time. The only time I have trouble is when I forget to wash the strap. It works optimally when washed every 5-7 uses. A sure sign it's time to wash the strap is when it starts to get crinkled and doesn't snap back to being flat like it was out of the box.