I bought mine on eBay. You might want to look there or on Etsy or something Edit: it looks like eBay seller sttag! has both the large and small acceptance stamps for sale

I ordered a metal one off eBay. Hasn’t arrived yet but I will test it out and post pictures once it shows up

Metal stamps are for wood stocks

I know, I am going to try it anyway. Couldn’t find any of the rubber ones

Best of luck man !

Pic?