Pachmyr are very nice modern, recoil reducing pads of many varieties. See Brownell's or Midway Sports. Some people like to put "vintage" reproduction pads on their vintage shotguns. Two that come to mind that are used frequently are a Hawkins replica which I like and a Silvers replica which I think is just a heavy piece of rubber...not particularly recoil reducing, but vintage in appearance.
For a modern field gun I would definitely go with a Pachmyr...I have 3 guns with them in place. One thing to consider is the desired length of pull. If you want a short length, you might go to Galazan for their 1/2" pad.
