Pretty much indestructible.  The Marathon Plus is an outstanding touring and everyday tire with SmartGuard flat protection that even a thumbtack can't penetrate.  Schwalbe calls it un-flatable!  The Marathon Plus is the most puncture resistant and most durable tire in Schwalbe's line and it is the most durable and puncture resistant tire we know of from any manufacturer.  

Please specify size in Notes, Questions and Substitution panel
26x1.35
26x1.5
26x1.75
700x25c
700x28c
700x32c
700x35c
700x38c