So I was super fortunate to have these available last night. We have a cat who suffers from chronic stress induced cystitis.  she was having a flareup and therefore urinated in multiple places in the house including the twin size bed that my daughter sleeps in. My husband slept in the urine soaked bed that night so as to not wake me up and infuriate me further. he then changed the sheets to the new ones the next day and the daughter slept in the bed once again. She rated the sheets as magnificent especially because they were not soaked in urine. My husband was so fortunate that these come equipped with a label that says top and bottom because he would not of figured it out.     The cat pictured is not the one who urinated in case you were wondering.