Clarks new adjustable back strap was too large to fit around heel and I could not adjust strap to fit. When I tried to tighten it, there was not enough Velcro to catch and hold.  The rest of the shoe fit well. Clarks obviously changed the heel back strap.  I have other pairs of this style with the non-adjustable back strap and have no problems with them.  Returned the sandals.