Definitely a self healing!! I have had two Olfa mats... 48"x36", plus a 36"x24", for 25 plus years. When I was sewing for my bread and butter, I butted them together so I could cut out patterns with my rotary cutter instead of scissors. They have been used for quilting now for about the last 15 yrs as well. Still going great!! I recently bought a folding unit to take to quilt retreat days...one side is Olfa self healing mat, the other side is a pressing mat. Love it!! A great item for removing the threads that sometimes get caught in the the cut marks is a bath scrubbie.
Patti