Are you referring to the R3 pad available on the Reminington website? Limbsaver makes a recoil pad that you can swap out on the Wingmaster. The model number is 10102. You can order from www.midwayusa.com. I'm not certain how the fit is (yet). If I have the time over the weekend I'll find out. I have one sitting on the desk and have been meaning to get to it for a few while now.

There's no reference to the 870 Express on the package or the Limbsaver website. I can't say if the dimension are the same for both models.