Sun Protection Factor, a measure of how well a particular S&W gun blocks the Sun's UV rays. Stainless guns reflect the most sunlight. Nickel guns reflect a bit less. Blued guns are carcinogenic because the dark color absorbs the UV rays and the free radicals in the frame steelwork transmit them to your skin.
Actually, it means Sold Pending Funds. If the funds don't materialize after a reasonable period of time and there's no communication between buyer and seller about it, you'll probably see the item back up for sale.
