https://www.amazon.com/gp/aw/d/B00APFN7DC/ref=mp_s_a_1_3?ie=UTF8&qid=1483506735&sr=8-3&pi=AC_SX236_SY340_QL65&keywords=Fountain+pen+kit&dpPl=1&dpID=3132q6MTyTL&ref=plSrch

Here's one, but WoodRiver probably has more on their site, and Penn State Industries also very likely has a few on their site.