Got a P-C 505 sander?  Eventually you'll need one of these as the foam between the mounting plate and the Stickit fabric will deteriorate and turn to dust.  The only real issue is the packaging.  It is a heat formed plastic over top of a cardboard display sheet.  Take care when peeling the plastic off the pad lest you bend the pad's thin aluminum backing plate.  Other than that, replacement is simple: Unscrew the 4 screws, remove and toss the old pad, put the new one in place and put the 4 screws back, and you're back in business.