the aluminum filter ring is available in 43mm, 46mm, and 49mm in addition to 39mm which comes with ALUM v2 (ALUM133). all filter rings are backwards compatible with ALUM v1.

when purchasing the adapter you receive the .step files under a gnu gpl license. you are then free to use the files as you wish, to make different casings, mounting adapter options and so on. you can share them with your friends, and share the changes you make.