These are 3D printed parts, designed and printed by me. They were originally designed for my own needs as I was having trouble finding suitable parts (used or now) and where I did, they were fairly expensive. Being plastic, these parts might not survive a zombie apocalypse necessarily but are reasonable alternatives to the OEM parts for less and effectively do the same thing (apart from defending from a zombie onslaught, anyway).
I am often adding new products or tweaking existing ones so the item you receive may not exactly match the product images, but will function in the same way.
I am also able to fairly easily customize these so if you require, for instance, a non-standard negative carrier, or an odd lens cone size, just let me know and I should be able to design something for you that fits your needs!