I recently bought the SK mystery box. As @falcaineer suggested, the boxes generally include pads. For the 15mm SK, you receive three 5.5" pads - blue, orange and white - to get you started. Mine actually came with three pairs of 4.5" SK Mini pads! Adam's order folks confirmed that was a packing error and they should all come with the correct size pads. I too have a Porter Cable, and I also have a Griot's Garage 3". I have put a 2" packing plate (Griot's BOSS) on the 3", as it's underpowered with a 3-4" pad (mine is an old GG unit) and it runs much better with a 2". I also have a 1"BP and pads from Detailer's Domain and just need some extension bars. The PC is now my 3" and isn't too much different on the vibe front. Very manageable and much more torque than the Griot's 3". The Swirl Killer is now my stock 5" (or 5.5" for pads) for larger panels and my PC 3" has both 3" (Griot's) and 4.5" (Adam's) pads, so some varying sizes and thickness of pads. I have a MINI and my wife has an SUV, so the range of sizes is really useful. I've used the SK today and I'm impressed. More comfortable to use than the PC and I like the extra throw.