FN 663226 FNX 15rd 45 ACP Black/Flat Dark Earth Steel
https://www.tandktactical.com/shop/845737002534-fn-663226-fnx-15rd-45-acp-black-flat-dark-earth-steel-12393
https://www.tandktactical.com/web/image/product.template/12393/image_1920?unique=0993f5b
This magazine is compatible with your FN FNX. It features a polished stainless steel body with a flat dark earth polymer base pad.