Lens board for Heidosmat 150mm f2.8 projector leans, to mount in 4x5 Graflex Speed Graphic cameras with Type C board mount. I secured the back of lens with a hose clamp and a rubber band. I'm sure there are tons of other ways to do the same. Made out of pla plus I can also make out of other materials if asked like Petg, Abs, Nylon just message me and ill let you know the cost Shipped out the next day! If you like another color let me know its default is Gray so message me so i can make the color you like before you purchase Gray Blue White Black Pink Orange Brown Purple Red Silver Yellow Copper Color Clear Pink Clear Purple Clear Blue Marble Army Green Wood Color Bone White