Yeyo - welcome to the site. You have a double die proof Eisenhower dollar. Unfortunately there are many, many doubled '71-S PF Eisenhowers out there (sometimes I think a non-doubled '71 proof IKE is rarer than one with doubling). Fortunately they're all cool, fortunately there's a group of folks out there (the Ike Group) who catalog these and fortunately some of these are worth a lot of money (I sold a double die reverse '71-S for $3,000 last month). I don't recognize you're variety as an established DiVA but I know less than 1/2 of 1% of what the Ike Group folks know. Check the IN GOD WE TRUST for splits in the serif's on the letters. Most of the valuable DDO's will show up there.
Nice find and keep hunting.