Glock 4th Gen recoil adapter ring

I've got an adapter ring for a 4th generation Glock (needed to install a 1-3 gen recoil spring assembly in a 4th gen slide). Paid 13$ on Amazon, will sell for $11 including shipping (1st class mail). Ring is black, here's the link to the listing of the same part in silver.

www.amazon.com/gp/product/B00AFK6IHO

Never used, I assumed my new pistol was 4th gen and turns out it isn't since the spring assembly I also got fits perfectly without the adapter. It's just too small and inexpensive to deal with a return but I've got no use for it and likely never will.

 

Here's the photo next to a penny for scale (suppose I could add the penny to the sale if need be...). Hard to get much detail since it's matte black finish, but it's a metal ring with a flange, fits into the front of the slide to adapt the gen 4 to fit a gen 1-3 spring/guide assembly.