Product review (5 stars): Love these!
Love these!  Smart - one large cube lasts longer, no more running back for more ice.  Provided your glass is large enough, these cubes make smaller cubes seem useless.  I got two for myself and one for a friend who also love it.  It's silicone so it is sturdy but it isn't hard plastic so it is flexible.  While you lose some sturdiness, you eliminate that difficulty in removing the cubes or in cracking the tray.