I know it has been awhile since I have had these in stock but I finally got some. I will sell them in 3 packs and cover the shipping cost.
https://www.edgunwest.com/store/p91/Edgun_Matador_R3%2FR2.5_Brass_Transfer_port_seal.html
https://www.edgunwest.com/store/p91/Edgun_Matador_R3%2FR2.5_Brass_Transfer_port_seal.html